blocks|key|5240443|text|如果要绑定到对象上的另一个属性：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5240444|{Binding+Path=PathToProperty,+RelativeSource={RelativeSource+Self}}|code-block|syntax|javascript|5240445|如果要获取祖先的属性，请执行以下操作：|5240446|{Binding+Path=PathToProperty,
++++RelativeSource={RelativeSource+AncestorType={x:Type+typeOfAncestor}}}|5240447|如果你想在模板化的父元素上获取一个属性(这样你就可以在一个ControlTemplate中进行双向绑定)|5240448|{Binding+Path=PathToProperty,+RelativeSource={RelativeSource+TemplatedParent}}|5240449|或者更短(这只适用于OneWay绑定)：|5240450|{TemplateBinding+Path=PathToProperty}|5240451|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

If you want to bind to another property on the object:

<pre><code>{Binding Path=PathToProperty, RelativeSource={RelativeSource Self}}
</code></pre>

If you want to get a property on an ancestor:

<pre><code>{Binding Path=PathToProperty,
 RelativeSource={RelativeSource AncestorType={x:Type typeOfAncestor}}}
</code></pre>

If you want to get a property on the templated parent (so you can do 2 way bindings in a ControlTemplate)

<pre><code>{Binding Path=PathToProperty, RelativeSource={RelativeSource TemplatedParent}}
</code></pre>

or, shorter (this only works for OneWay bindings):

<pre><code>{TemplateBinding Path=PathToProperty}
</code></pre>

blocks|key|5240528|text|Binding+RelativeSource={
++++RelativeSource+Mode=FindAncestor,+AncestorType={x:Type+ItemType}
}
...|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|5240529|RelativeSource的默认属性是Mode属性。这里给出了一组完整的有效值(from+MSDN)：|unstyled|offset|length|style|CODE|5240530|displayed.|5240531|TemplatedParent+|unordered-list-item|5240532|PreviousData允许您绑定数据项列表中的前一个数据项(而不是包含该数据项的控件)，该数据项列表引用模板(其中存在数据绑定元素)所应用的元素。这类似于设置TemplateBindingExtension，并且仅在绑定位于模板内时适用。|5240533|Self是指在其上设置绑定的元素，并允许您将该元素的一个属性绑定到数据绑定元素父链中的另一个属性。Self引用数据绑定元素的父链中的祖先。您可以使用它绑定到特定类型的祖先或其子类。如果要指定AncestorType和/或AncestorLevel.|5240534|，则使用此模式|5240535|5240536|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.windows.data.relativesourcemode.aspx^0|0|0|E|K|4|15|9|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|15|8|@$G|16|H|17|I|J]|$G|18|H|19|I|J]]|9|@$G|1A|H|1B|1|1C]]|A|$]]|$1|K|3|L|5|F|7|1D|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|1E|8|@]|9|@]|A|$]]|$1|P|3|Q|5|O|7|1F|8|@]|9|@]|A|$]]|$1|R|3|S|5|O|7|1G|8|@]|9|@]|A|$]]|$1|T|3|U|5|F|7|1H|8|@]|9|@]|A|$]]|$1|V|3|-4|5|F|7|1I|8|@]|9|@]|A|$]]|$1|W|3|-4|5|F|7|1J|8|@]|9|@]|A|$]]]|X|$Y|$5|Z|10|11|A|$12|13]]]]

<pre><code>Binding RelativeSource={
 RelativeSource Mode=FindAncestor, AncestorType={x:Type ItemType}
}
...
</code></pre>

The default attribute of <code>RelativeSource</code> is the <code>Mode</code> property. A complete set of valid values is given here (<a href="http://msdn.microsoft.com/en-us/library/system.windows.data.relativesourcemode.aspx" rel="noreferrer">from MSDN</a>):

<ul>
<li>PreviousData Allows you to bind the previous data item (not that control that contains the data item) in the list of data items being displayed.</li>
<li>TemplatedParent Refers to the element to which the template (in which the data-bound element exists) is applied. This is similar to setting a TemplateBindingExtension and is only applicable if the Binding is within a template.</li>
<li>Self Refers to the element on which you are setting the binding and allows you to bind one property of that element to another property on the same element.</li>
<li>FindAncestor Refers to the ancestor in the parent chain of the data-bound element. You can use this to bind to an ancestor of a specific type or its subclasses. This is the mode you use if you want to specify AncestorType and/or AncestorLevel.</li>
</ul>

blocks|key|5240638|text|在MVVM架构的上下文中有一个更直观的解释：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5240639|​|5240640|📷|atomic|offset|length|5240641|5240642|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/5abf03b5f8af64df1a879a88049aaa01.jpeg|imageAlt^0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@$G|V|H|W|1|X]]|A|$]]|$1|I|3|C|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q|R|-4]]]]

Here's a more visual explanation in the context of a MVVM architecture:

<img src="https://i.stack.imgur.com/6Tcc6.jpg" alt="enter image description here">

blocks|key|3830344|text|Bechir+Bejaoui在his+article+here中展示了RelativeSources在WPF中的用例|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3830345|XAML是一个标记扩展，当我们试图将一个给定对象的属性绑定到对象本身的另一个属性时，当我们试图将一个对象的属性绑定到它的另一个相对父级时，当我们在自定义控件开发的情况下将依赖属性值绑定到一段|3830346|时，最后在使用一系列绑定数据的差分的情况下，RelativeSource是一个标记扩展。所有这些情况都表示为相对源模式。我将逐一揭露所有这些案例。|blockquote|3830347|3830348|3830349|3830350|模式本身：|ordered-list-item|3830351|3830352|想象一下这个例子，我们想要一个矩形，它的高度总是等于它的宽度，比如说一个正方形。我们可以使用元素名来做到这一点|3830353|3830354|但在上面的情况下，我们必须指出绑定对象的名称，即矩形。我们可以使用RelativeSource以不同的方式达到相同的目的|3830355|3830356|在这种情况下，我们没有必要提到绑定对象的名称，并且每当高度改变时，宽度都将始终等于高度。|3830357|如果您想将宽度参数设置为高度的一半，那么可以通过向绑定标记扩展添加一个转换器来实现。现在让我们想象另一个案例：|3830358|3830359|上面的用例用于将给定元素的给定属性绑定到其直接父元素之一，因为该元素拥有一个称为父元素的属性。这将我们引向另一种相对源模式，即FindAncestor模式。|3830360|3830361|模式FindAncestor|3830362|3830363|在这种情况下，给定元素的属性将被绑定到它的父元素Corse。与上述情况的主要区别是，这取决于您确定祖先类型和祖先在层次结构中的排名，以连接属性。顺便说一句，试着使用这段XAML|3830364|3830365|上面的情况是两个TextBlock元素，它们嵌入在一系列的边框和画布元素中，它们代表了它们的分层父元素。第二个TextBlock将在相对源代码级别显示给定父级的名称。|3830366|因此，尝试将AncestorLevel=2更改为AncestorLevel=1，看看会发生什么情况。然后尝试将祖先的类型从AncestorType=Border更改为AncestorType=Canvas，看看会发生什么。|3830367|显示的文本将根据祖先类型和级别而变化。那么，如果祖先级别不适合祖先类型，会发生什么？这是一个很好的问题，我知道你将要问它。响应是不会抛出任何异常，并且不会在TextBlock级别显示任何内容。|3830368|3830369|TemplatedParent|3830370|3830371|此模式允许将给定的ControlTemplate属性绑定到应用ControlTemplate的控件的属性。为了更好地理解这个问题，下面是一个示例|3830372|+++单击我|3830373|如果我想将给定控件的属性应用于它的控件模板，那么我可以使用TemplatedParent模式。还有一个与此标记扩展类似的扩展，即TemplateBinding，它是第一个扩展的缩写，但TemplateBinding是在编译时计算的，而TemplatedParent的计算恰好在第一个运行时之后。如下图所示，背景和内容是从按钮内部应用到控件模板的。|3830374|entityMap|0|LINK|mutability|MUTABLE|url|http://www.c-sharpcorner.com/UploadFile/yougerthen/relativesources-in-wpf/^0|F|G|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1X|8|@]|9|@$A|1Y|B|1Z|1|20]]|C|$]]|$1|D|3|E|5|6|7|21|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|22|8|@]|9|@]|C|$]]|$1|I|3|-4|5|6|7|23|8|@]|9|@]|C|$]]|$1|J|3|-4|5|6|7|24|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|25|8|@]|9|@]|C|$]]|$1|L|3|M|5|N|7|26|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|27|8|@]|9|@]|C|$]]|$1|P|3|Q|5|6|7|28|8|@]|9|@]|C|$]]|$1|R|3|-4|5|6|7|29|8|@]|9|@]|C|$]]|$1|S|3|T|5|6|7|2A|8|@]|9|@]|C|$]]|$1|U|3|-4|5|6|7|2B|8|@]|9|@]|C|$]]|$1|V|3|W|5|6|7|2C|8|@]|9|@]|C|$]]|$1|X|3|Y|5|6|7|2D|8|@]|9|@]|C|$]]|$1|Z|3|-4|5|6|7|2E|8|@]|9|@]|C|$]]|$1|10|3|11|5|6|7|2F|8|@]|9|@]|C|$]]|$1|12|3|-4|5|6|7|2G|8|@]|9|@]|C|$]]|$1|13|3|14|5|N|7|2H|8|@]|9|@]|C|$]]|$1|15|3|-4|5|6|7|2I|8|@]|9|@]|C|$]]|$1|16|3|17|5|6|7|2J|8|@]|9|@]|C|$]]|$1|18|3|-4|5|6|7|2K|8|@]|9|@]|C|$]]|$1|19|3|1A|5|6|7|2L|8|@]|9|@]|C|$]]|$1|1B|3|1C|5|6|7|2M|8|@]|9|@]|C|$]]|$1|1D|3|1E|5|6|7|2N|8|@]|9|@]|C|$]]|$1|1F|3|-4|5|6|7|2O|8|@]|9|@]|C|$]]|$1|1G|3|1H|5|N|7|2P|8|@]|9|@]|C|$]]|$1|1I|3|-4|5|6|7|2Q|8|@]|9|@]|C|$]]|$1|1J|3|1K|5|6|7|2R|8|@]|9|@]|C|$]]|$1|1L|3|1M|5|6|7|2S|8|@]|9|@]|C|$]]|$1|1N|3|1O|5|6|7|2T|8|@]|9|@]|C|$]]|$1|1P|3|-4|5|6|7|2U|8|@]|9|@]|C|$]]]|1Q|$1R|$5|1S|1T|1U|C|$1V|1W]]]]

Bechir Bejaoui exposes the use cases of the RelativeSources in WPF in <a href="http://www.c-sharpcorner.com/UploadFile/yougerthen/relativesources-in-wpf/">his article here</a>:

<blockquote>
 The RelativeSource is a markup extension that is used in particular
 binding cases when we try to bind a property of a given object to
 another property of the object itself, when we try to bind a property
 of a object to another one of its relative parents, when binding a
 dependency property value to a piece of XAML in case of custom control
 development and finally in case of using a differential of a series of
 a bound data. All of those situations are expressed as relative source
 modes. I will expose all of those cases one by one.
 
 <ol>
 <li>Mode Self:</li>
 </ol>
 
 Imagine this case, a rectangle that we want that its height is always
 equal to its width, a square let's say. We can do this using the
 element name

<pre><code>&lt;Rectangle Fill="Red" Name="rectangle" 
 Height="100" Stroke="Black" 
 Canvas.Top="100" Canvas.Left="100"
 Width="{Binding ElementName=rectangle,
 Path=Height}"/&gt;
</code></pre>
 
 But in this above case we are obliged to indicate the name of the
 binding object, namely the rectangle. We can reach the same purpose
 differently using the RelativeSource 

<pre><code>&lt;Rectangle Fill="Red" Height="100" 
 Stroke="Black" 
 Width="{Binding RelativeSource={RelativeSource Self},
 Path=Height}"/&gt;
</code></pre>
 
 For that case we are not obliged to mention the name of the binding
 object and the Width will be always equal to the Height whenever the
 height is changed. 
 
 If you want to parameter the Width to be the half of the height then
 you can do this by adding a converter to the Binding markup extension.
 Let's imagine another case now:

<pre><code> &lt;TextBlock Width="{Binding RelativeSource={RelativeSource Self},
 Path=Parent.ActualWidth}"/&gt;
</code></pre>
 
 The above case is used to tie a given property of a given element to
 one of its direct parent ones as this element holds a property that is
 called Parent. This leads us to another relative source mode which is
 the FindAncestor one. 
 
 <ol>
 <li>Mode FindAncestor</li>
 </ol>
 
 In this case, a property of a given element will be tied to one of its
 parents, Of Corse. The main difference with the above case is the fact
 that, it's up to you to determine the ancestor type and the ancestor
 rank in the hierarchy to tie the property. By the way try to play with
 this piece of XAML

<pre><code>&lt;Canvas Name="Parent0"&gt;
 &lt;Border Name="Parent1"
 Width="{Binding RelativeSource={RelativeSource Self},
 Path=Parent.ActualWidth}"
 Height="{Binding RelativeSource={RelativeSource Self},
 Path=Parent.ActualHeight}"&gt;
 &lt;Canvas Name="Parent2"&gt;
 &lt;Border Name="Parent3"
 Width="{Binding RelativeSource={RelativeSource Self},
 Path=Parent.ActualWidth}"
 Height="{Binding RelativeSource={RelativeSource Self},
 Path=Parent.ActualHeight}"&gt;
 &lt;Canvas Name="Parent4"&gt;
 &lt;TextBlock FontSize="16" 
 Margin="5" Text="Display the name of the ancestor"/&gt;
 &lt;TextBlock FontSize="16" 
 Margin="50" 
 Text="{Binding RelativeSource={RelativeSource 
 FindAncestor,
 AncestorType={x:Type Border}, 
 AncestorLevel=2},Path=Name}" 
 Width="200"/&gt;
 &lt;/Canvas&gt;
 &lt;/Border&gt;
 &lt;/Canvas&gt;
 &lt;/Border&gt;
 &lt;/Canvas&gt;
</code></pre>
 
 The above situation is of two TextBlock elements those are embedded
 within a series of borders and canvas elements those represent their
 hierarchical parents. The second TextBlock will display the name of
 the given parent at the relative source level.
 
 So try to change AncestorLevel=2 to AncestorLevel=1 and see what
 happens. Then try to change the type of the ancestor from
 AncestorType=Border to AncestorType=Canvas and see what's happens. 
 
 The displayed text will change according to the Ancestor type and
 level. Then what's happen if the ancestor level is not suitable to the
 ancestor type? This is a good question, I know that you're about to
 ask it. The response is no exceptions will be thrown and nothings will
 be displayed at the TextBlock level. 
 
 <ol>
 <li>TemplatedParent</li>
 </ol>
 
 This mode enables tie a given ControlTemplate property to a property
 of the control that the ControlTemplate is applied to. To well
 understand the issue here is an example bellow

<pre><code>&lt;Window.Resources&gt;
&lt;ControlTemplate x:Key="template"&gt;
 &lt;Canvas&gt;
 &lt;Canvas.RenderTransform&gt;
 &lt;RotateTransform Angle="20"/&gt;
 &lt;/Canvas.RenderTransform&gt;
 &lt;Ellipse Height="100" Width="150" 
 Fill="{Binding 
 RelativeSource={RelativeSource TemplatedParent},
 Path=Background}"&gt;

 &lt;/Ellipse&gt;
 &lt;ContentPresenter Margin="35" 
 Content="{Binding RelativeSource={RelativeSource 
 TemplatedParent},Path=Content}"/&gt;
 &lt;/Canvas&gt;
 &lt;/ControlTemplate&gt;
&lt;/Window.Resources&gt;
 &lt;Canvas Name="Parent0"&gt;
 &lt;Button Margin="50" 
 Template="{StaticResource template}" Height="0" 
 Canvas.Left="0" Canvas.Top="0" Width="0"&gt;
 &lt;TextBlock FontSize="22"&gt;Click me&lt;/TextBlock&gt;
 &lt;/Button&gt;
 &lt;/Canvas&gt;
</code></pre>
 
 If I want to apply the properties of a given control to its control
 template then I can use the TemplatedParent mode. There is also a
 similar one to this markup extension which is the TemplateBinding
 which is a kind of short hand of the first one, but the
 TemplateBinding is evaluated at compile time at the contrast of the
 TemplatedParent which is evaluated just after the first run time. As
 you can remark in the bellow figure, the background and the content
 are applied from within the button to the control template.
</blockquote>

blocks|key|746004|text|WPF+RelativeSource+properties+binding中的公开了三个要设置的：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|746005|1.模式：这是一个可能有四个值的enum：|746006|PreviousData(value=0):+|746007|+a.它将property的前一个值赋给绑定的值|blockquote|746008|746009|TemplatedParent(value=1):+b.+b.当定义任何控件的templates并希望绑定到control的值/属性时，使用此选项。|746010|例如，定义ControlTemplate：|746011|746012|++<ControlTemplate>
++++++++<CheckBox+IsChecked="{Binding+RelativeSource={RelativeSource+TemplatedParent},+Path=Value,+Mode=TwoWay,+UpdateSourceTrigger=PropertyChanged}"+/>
+</ControlTemplate>|code-block|syntax|javascript|746013|当我们想要从self的self或property进行绑定时，|746014|+c.Self。|746015|746016|例如：将checkbox的选中状态发送为CommandParameter，同时在CheckBox上设置Command|746017|746018|<CheckBox+......+CommandParameter="{Binding+RelativeSource={RelativeSource+Self},Path=IsChecked}"+/>|746019|当要从|746020|中的父control绑定时，使用+d.+control。|746021|746022|例如：+Bind+a+checkbox+in+records+if+a+grid，if+header+checkbox被选中|746023|746024|<CheckBox+IsChecked="{Binding+RelativeSource={RelativeSource+Mode=FindAncestor,+AncestorType={x:Type+iDP:XamDataGrid}},+Path=DataContext.IsHeaderChecked,+Mode=TwoWay}"+/>|746025|2.+AncestorType:当模式为FindAncestor时，定义祖先的类型|746026|RelativeSource={RelativeSource+Mode=FindAncestor,+AncestorType={x:Type+iDP:XamDataGrid}}|746027|3.+AncestorLevel:当模式为FindAncestor时，是什么级别的祖先(如果visual+tree中有两个相同类型的父节点)|746028|RelativeSource={RelativeSource+Mode=FindAncestor,+AncestorType={x:Type+iDP:XamDataGrid,+AncestorLevel=1}}|746029|上面的|746030|都是RelativeSource+binding.的用例|746031|746032|746033|.|746034|entityMap^0|4|E|J|A|13|A|4|E|J|A|0|0|L|G|4|0|0|M|D|7|0|1|N|5|8|0|0|0|P|T|19|G|7|13|9|1I|7|0|0|3|5|F|0|0|0|B|4|G|8|0|1|7|0|0|0|1M|4|8|K|G|14|8|1F|7|0|0|0|0|3|0|0|G|H|B|3|7|K|7|0|0|0|1E|1F|B|B|8|N|7|10|4|18|6|1F|8|0|0|0|0|15|K|C|0|0|0|1Y|L|C|1A|B|0|0|0|3|0|0|S|2|M|0|0|0|0|1|0^^$0|@$1|2|3|4|5|6|7|20|8|@$9|21|A|22|B|C]|$9|23|A|24|B|C]|$9|25|A|26|B|C]|$9|27|A|28|B|D]|$9|29|A|2A|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|2B|8|@$9|2C|A|2D|B|C]|$9|2E|A|2F|B|D]]|E|@]|F|$]]|$1|I|3|J|5|6|7|2G|8|@$9|2H|A|2I|B|C]|$9|2J|A|2K|B|D]]|E|@]|F|$]]|$1|K|3|L|5|M|7|2L|8|@$9|2M|A|2N|B|C]|$9|2O|A|2P|B|D]]|E|@]|F|$]]|$1|N|3|-4|5|6|7|2Q|8|@]|E|@]|F|$]]|$1|O|3|P|5|6|7|2R|8|@$9|2S|A|2T|B|C]|$9|2U|A|2V|B|C]|$9|2W|A|2X|B|D]|$9|2Y|A|2Z|B|D]|$9|30|A|31|B|D]]|E|@]|F|$]]|$1|Q|3|R|5|6|7|32|8|@$9|33|A|34|B|C]|$9|35|A|36|B|D]]|E|@]|F|$]]|$1|S|3|-4|5|6|7|37|8|@]|E|@]|F|$]]|$1|T|3|U|5|V|7|38|8|@]|E|@]|F|$W|X]]|$1|Y|3|Z|5|6|7|39|8|@$9|3A|A|3B|B|D]|$9|3C|A|3D|B|D]]|E|@]|F|$]]|$1|10|3|11|5|M|7|3E|8|@$9|3F|A|3G|B|C]]|E|@]|F|$]]|$1|12|3|-4|5|6|7|3H|8|@]|E|@]|F|$]]|$1|13|3|14|5|6|7|3I|8|@$9|3J|A|3K|B|C]|$9|3L|A|3M|B|D]|$9|3N|A|3O|B|D]|$9|3P|A|3Q|B|D]|$9|3R|A|3S|B|D]]|E|@]|F|$]]|$1|15|3|-4|5|6|7|3T|8|@]|E|@]|F|$]]|$1|16|3|17|5|V|7|3U|8|@]|E|@]|F|$W|X]]|$1|18|3|19|5|6|7|3V|8|@$9|3W|A|3X|B|C]]|E|@]|F|$]]|$1|1A|3|1B|5|M|7|3Y|8|@$9|3Z|A|40|B|C]|$9|41|A|42|B|C]|$9|43|A|44|B|D]|$9|45|A|46|B|D]]|E|@]|F|$]]|$1|1C|3|-4|5|6|7|47|8|@]|E|@]|F|$]]|$1|1D|3|1E|5|6|7|48|8|@$9|49|A|4A|B|C]|$9|4B|A|4C|B|C]|$9|4D|A|4E|B|D]|$9|4F|A|4G|B|D]|$9|4H|A|4I|B|D]|$9|4J|A|4K|B|D]|$9|4L|A|4M|B|D]]|E|@]|F|$]]|$1|1F|3|-4|5|6|7|4N|8|@]|E|@]|F|$]]|$1|1G|3|1H|5|V|7|4O|8|@]|E|@]|F|$W|X]]|$1|1I|3|1J|5|6|7|4P|8|@$9|4Q|A|4R|B|C]|$9|4S|A|4T|B|D]]|E|@]|F|$]]|$1|1K|3|1L|5|V|7|4U|8|@]|E|@]|F|$W|X]]|$1|1M|3|1N|5|6|7|4V|8|@$9|4W|A|4X|B|C]|$9|4Y|A|4Z|B|D]|$9|50|A|51|B|D]]|E|@]|F|$]]|$1|1O|3|1P|5|V|7|52|8|@]|E|@]|F|$W|X]]|$1|1Q|3|1R|5|6|7|53|8|@$9|54|A|55|B|C]]|E|@]|F|$]]|$1|1S|3|1T|5|M|7|56|8|@$9|57|A|58|B|C]|$9|59|A|5A|B|D]]|E|@]|F|$]]|$1|1U|3|-4|5|6|7|5B|8|@]|E|@]|F|$]]|$1|1V|3|-4|5|6|7|5C|8|@]|E|@]|F|$]]|$1|1W|3|1X|5|6|7|5D|8|@$9|5E|A|5F|B|C]]|E|@]|F|$]]|$1|1Y|3|-4|5|6|7|5G|8|@]|E|@]|F|$]]]|1Z|$]]

In WPF <code>RelativeSource</code> binding exposes three <code>properties</code> to set:

1. Mode: This is an <code>enum</code> that could have four values:

<blockquote>
 a. PreviousData(<code>value=0</code>): It assigns the previous value of the <code>property</code> to
 the bound one
 
 b. TemplatedParent(<code>value=1</code>): This is used when defining the <code>templates</code> of
 any control and want to bind to a value/Property of the <code>control</code>.
 
 For example, define <code>ControlTemplate</code>:
</blockquote>

<pre><code> &lt;ControlTemplate&gt;
 &lt;CheckBox IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Value, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" /&gt;
 &lt;/ControlTemplate&gt;
</code></pre>

<blockquote>
 c. Self(<code>value=2</code>): When we want to bind from a <code>self</code> or a <code>property</code> of self.
 
 For example: Send checked state of <code>checkbox</code> as <code>CommandParameter</code> while setting the <code>Command</code> on <code>CheckBox</code>
</blockquote>

<pre><code>&lt;CheckBox ...... CommandParameter="{Binding RelativeSource={RelativeSource Self},Path=IsChecked}" /&gt;
</code></pre>

<blockquote>
 d. FindAncestor(<code>value=3</code>): When want to bind from a parent <code>control</code>
 in <code>Visual Tree</code>.
 
 For example: Bind a <code>checkbox</code> in <code>records</code> if a <code>grid</code>,if <code>header</code> <code>checkbox</code> is checked
</blockquote>

<pre><code>&lt;CheckBox IsChecked="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type iDP:XamDataGrid}}, Path=DataContext.IsHeaderChecked, Mode=TwoWay}" /&gt;
</code></pre>

2. AncestorType: when mode is <code>FindAncestor</code> then define what type of ancestor

<pre><code>RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type iDP:XamDataGrid}}
</code></pre>

3. AncestorLevel: when mode is <code>FindAncestor</code> then what level of ancestor (if there are two same type of parent in <code>visual tree</code>)

<pre><code>RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type iDP:XamDataGrid, AncestorLevel=1}}
</code></pre>

<blockquote>
 Above are all use-cases for <code>RelativeSource binding</code>.
</blockquote>

<a href="http://www.nbdtech.com/Free/WpfBinding.pdf" rel="noreferrer">Here is a reference link</a>.

blocks|key|749171|text|别忘了TemplatedParent：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|749172|<Binding+RelativeSource="{RelativeSource+TemplatedParent}"/>|code-block|syntax|javascript|749173|或|749174|{Binding+RelativeSource={RelativeSource+TemplatedParent}}|749175|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Don't forget TemplatedParent:

<pre><code>&lt;Binding RelativeSource="{RelativeSource TemplatedParent}"/&gt;
</code></pre>

or

<pre><code>{Binding RelativeSource={RelativeSource TemplatedParent}}
</code></pre>

blocks|key|3830067|text|值得注意的是，对于那些偶然发现Silverlight这种想法的人：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3830068|Silverlight只提供了这些命令中的一个精简子集|3830069|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

It's worthy of note that for those stumbling across this thinking of Silverlight:

Silverlight offers a reduced subset only, of these commands

blocks|key|745873|text|我创建了一个库来简化WPF的绑定语法，包括使其更易于使用RelativeSource。这里有一些例子。之前：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|745874|{Binding+Path=PathToProperty,+RelativeSource={RelativeSource+Self}}
{Binding+Path=PathToProperty,+RelativeSource={RelativeSource+AncestorType={x:Type+typeOfAncestor}}}
{Binding+Path=PathToProperty,+RelativeSource={RelativeSource+TemplatedParent}}
{Binding+Path=Text,+ElementName=MyTextBox}|code-block|syntax|javascript|745875|之后：|745876|{BindTo+PathToProperty}
{BindTo+Ancestor.typeOfAncestor.PathToProperty}
{BindTo+Template.PathToProperty}
{BindTo+#MyTextBox.Text}|745877|下面是一个如何简化方法绑定的示例。之前：|745878|//+C#+code
private+ICommand+_saveCommand;
public+ICommand+SaveCommand+{
+get+{
++if+(_saveCommand+==+null)+{
+++_saveCommand+=+new+RelayCommand(x+=>+this.SaveObject());
++}
++return+_saveCommand;
+}
}

private+void+SaveObject()+{
+//+do+something
}

//+XAML
{Binding+Path=SaveCommand}|745879|745880|//+C#+code
private+void+SaveObject()+{
+//+do+something
}

//+XAML
{BindTo+SaveObject()}|745881|你可以在这里找到这个库：http://www.simplygoodcode.com/2012/08/simpler-wpf-binding.html|offset|length|745882|请注意，在我用于方法绑定的“BEFORE”示例中，代码已经使用RelayCommand进行了优化，我最后检查它不是WPF的本机部分。如果没有这一点，“之前”的例子会更长。|style|CODE|745883|entityMap|0|LINK|mutability|MUTABLE|url|http://www.simplygoodcode.com/2012/08/simpler-wpf-binding.html^0|0|0|0|0|0|0|0|0|C|1Q|0|0|V|C|0^^$0|@$1|2|3|4|5|6|7|17|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|18|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|19|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|1B|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|1C|8|@]|9|@]|A|$E|F]]|$1|O|3|H|5|6|7|1D|8|@]|9|@]|A|$]]|$1|P|3|Q|5|D|7|1E|8|@]|9|@]|A|$E|F]]|$1|R|3|S|5|6|7|1F|8|@]|9|@$T|1G|U|1H|1|1I]]|A|$]]|$1|V|3|W|5|6|7|1J|8|@$T|1K|U|1L|X|Y]]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1M|8|@]|9|@]|A|$]]]|10|$11|$5|12|13|14|A|$15|16]]]]

I created a library to simplify the binding syntax of WPF including making it easier to use RelativeSource. Here are some examples. Before:

<pre><code>{Binding Path=PathToProperty, RelativeSource={RelativeSource Self}}
{Binding Path=PathToProperty, RelativeSource={RelativeSource AncestorType={x:Type typeOfAncestor}}}
{Binding Path=PathToProperty, RelativeSource={RelativeSource TemplatedParent}}
{Binding Path=Text, ElementName=MyTextBox}
</code></pre>

After:

<pre><code>{BindTo PathToProperty}
{BindTo Ancestor.typeOfAncestor.PathToProperty}
{BindTo Template.PathToProperty}
{BindTo #MyTextBox.Text}
</code></pre>

Here is an example of how method binding is simplified. Before:

<pre><code>// C# code
private ICommand _saveCommand;
public ICommand SaveCommand {
 get {
 if (_saveCommand == null) {
 _saveCommand = new RelayCommand(x =&gt; this.SaveObject());
 }
 return _saveCommand;
 }
}

private void SaveObject() {
 // do something
}

// XAML
{Binding Path=SaveCommand}
</code></pre>

After:

<pre><code>// C# code
private void SaveObject() {
 // do something
}

// XAML
{BindTo SaveObject()}
</code></pre>

You can find the library here: <a href="http://www.simplygoodcode.com/2012/08/simpler-wpf-binding.html">http://www.simplygoodcode.com/2012/08/simpler-wpf-binding.html</a>

Note in the 'BEFORE' example that I use for method binding that code was already optimized by using <code>RelayCommand</code> which last I checked is not a native part of WPF. Without that the 'BEFORE' example would have been even longer.

blocks|key|5240736|text|一些有用的零碎内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5240737|以下是如何在代码中完成此操作的主要步骤：|5240738|Binding+b+=+new+Binding();
b.RelativeSource+=+new+RelativeSource(RelativeSourceMode.FindAncestor,+this.GetType(),+1);
b.Path+=+new+PropertyPath("MyElementThatNeedsBinding");
MyLabel.SetBinding(ContentProperty,+b);|code-block|syntax|javascript|5240739|我很大程度上是从上复制的。|5240740|而且，就示例而言，MSDN页面相当不错：|5240741|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Some useful bits and pieces:

Here's how to do it mostly in code:

<pre class="lang-cs prettyprint-override"><code>Binding b = new Binding();
b.RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor, this.GetType(), 1);
b.Path = new PropertyPath("MyElementThatNeedsBinding");
MyLabel.SetBinding(ContentProperty, b);
</code></pre>

I largely copied this from <a href="http://social.msdn.microsoft.com/Forums/en/wpf/thread/c5a59f07-c932-4715-8774-fa7e8472b75b" rel="nofollow noreferrer">Binding Relative Source in code Behind</a>.

Also, the MSDN page is pretty good as far as examples go: <a href="http://msdn.microsoft.com/en-us/library/system.windows.data.relativesource.aspx" rel="nofollow noreferrer">RelativeSource Class</a>

blocks|key|3830075|text|我刚刚发布了访问Silverlight中父元素的DataContext的，这对我来说很有效。它使用Binding+ElementName。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3830076|entityMap^0|1D|J|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

I just posted <a href="https://stackoverflow.com/questions/3404707/wpf-access-parent-datacontext-from-datatemplate/3547707#3547707">another solution</a> for accessing the DataContext of a parent element in Silverlight that works for me. It uses <code>Binding ElementName</code>.

blocks|key|746060|text|我没有读完所有的答案，但我只是想在相对源命令绑定按钮的情况下添加这些信息。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|746061|当您在Mode=FindAncestor中使用相对源代码时，绑定必须如下所示：|offset|length|style|CODE|746062|Command="{Binding+Path=DataContext.CommandProperty,+RelativeSource={...}}"|code-block|syntax|javascript|746063|如果您不在路径中添加DataContext，那么在执行时它将无法检索该属性。|746064|entityMap^0|0|3|H|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|U|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I didn't read every answer, but I just want to add this information in case of relative source command binding of a button.

When you use a relative source with <code>Mode=FindAncestor</code>, the binding must be like:

<pre><code>Command="{Binding Path=DataContext.CommandProperty, RelativeSource={...}}"
</code></pre>

If you don't add DataContext in your path, at execution time it can't retrieve the property.

blocks|key|3830443|text|这是一个使用此模式的示例，该模式在空数据网格上对我有效。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3830444|<Style.Triggers>
++++<DataTrigger+Binding="{Binding+Items.Count,+RelativeSource={RelativeSource+Self}}"+Value="0">
++++++++<Setter+Property="Background">
++++++++++++<Setter.Value>
++++++++++++++++<VisualBrush+Stretch="None">
++++++++++++++++++++<VisualBrush.Visual>
++++++++++++++++++++++++<TextBlock+Text="We+did't+find+any+matching+records+for+your+search..."+FontSize="16"+FontWeight="SemiBold"+Foreground="LightCoral"/>
++++++++++++++++++++</VisualBrush.Visual>
++++++++++++++++</VisualBrush>
++++++++++++</Setter.Value>
++++++++</Setter>
++++</DataTrigger>
</Style.Triggers>|code-block|syntax|javascript|3830445|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is an example of the use of this pattern that worked for me on empty datagrids.

<pre><code>&lt;Style.Triggers&gt;
 &lt;DataTrigger Binding="{Binding Items.Count, RelativeSource={RelativeSource Self}}" Value="0"&gt;
 &lt;Setter Property="Background"&gt;
 &lt;Setter.Value&gt;
 &lt;VisualBrush Stretch="None"&gt;
 &lt;VisualBrush.Visual&gt;
 &lt;TextBlock Text="We did't find any matching records for your search..." FontSize="16" FontWeight="SemiBold" Foreground="LightCoral"/&gt;
 &lt;/VisualBrush.Visual&gt;
 &lt;/VisualBrush&gt;
 &lt;/Setter.Value&gt;
 &lt;/Setter&gt;
 &lt;/DataTrigger&gt;
&lt;/Style.Triggers&gt;
</code></pre>

blocks|key|5241187|text|如果一个元素不是可视化树的一部分，那么RelativeSource将永远不会工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5241188|在这种情况下，您需要尝试一种由Thomas+Levesque首创的不同技术。|5241189|他在[WPF]+How+to+bind+to+data+when+the+DataContext+is+not+inherited下的博客上提供了解决方案。而且它的工作非常出色！|offset|length|5241190|万一他的博客宕机了，附录A中包含了his+article的镜像副本。|5241191|请不要在这里发表评论，请。|5241192|附录A:博客文章的镜像|5241193|WPF中的DataContext属性非常方便，因为分配它的元素的所有子元素都会自动继承它；因此，您不需要在每个要绑定的元素上重新设置它。但是，在某些情况下，DataContext是不可访问的:这种情况发生在不属于可视或逻辑树的元素上。因此，在这些元素上绑定属性…可能非常困难|5241194|让我们用一个简单的例子来说明:我们想要在DataGrid中显示一个产品列表。在网格中，我们希望能够根据ViewModel公开的ShowPrice属性的值来显示或隐藏Price列。最明显的方法是将列的可见性绑定到ShowPrice属性：|5241195|<DataGridTextColumn+Header="Price"+Binding="{Binding+Price}"+IsReadOnly="False"
++++++++++++++++Visibility="{Binding+ShowPrice,
++++++++++++++++Converter={StaticResource+visibilityConverter}}"/>|code-block|syntax|javascript|5241196|遗憾的是，更改ShowPrice的值没有任何影响，并且该列始终是可见的…为什么？如果我们在Visual+Studio中查看Output窗口，我们会注意到下面这一行：|5241197|5241198|+System.Windows.Data错误:2:找不到目标元素的管理FrameworkElement或FrameworkContentElement。可见性；可见性；目标元素为‘DataGridTextColumn’(HashCode=32685253)；目标属性为‘Visibility’(类型为‘Visibility’)|blockquote|5241199|5241200|该消息相当神秘，但其含义实际上相当简单:+WPF不知道使用哪个FrameworkElement来获取DataContext，因为该列不属于DataGrid的可视或逻辑树。|5241201|5241202|我们可以尝试调整绑定以获得所需的结果，例如，通过将RelativeSource设置为DataGrid本身：|5241203|<DataGridTextColumn+Header="Price"+Binding="{Binding+Price}"+IsReadOnly="False"
++++++++++++++++Visibility="{Binding+DataContext.ShowPrice,
++++++++++++++++Converter={StaticResource+visibilityConverter},
++++++++++++++++RelativeSource={RelativeSource+FindAncestor,+AncestorType=DataGrid}}"/>|5241204|或者，我们可以添加一个绑定到ShowPrice的CheckBox，并尝试通过指定元素名称将列可见性绑定到IsChecked属性：|5241205|<DataGridTextColumn+Header="Price"+Binding="{Binding+Price}"+IsReadOnly="False"
++++++++++++++++Visibility="{Binding+IsChecked,
++++++++++++++++Converter={StaticResource+visibilityConverter},
++++++++++++++++ElementName=chkShowPrice}"/>|5241206|但是这些变通方法似乎都不起作用，我们总是得到相同的结果…|5241207|在这一点上，似乎唯一可行的方法是更改代码隐藏中的列可见性，这是我们在使用MVVM模式…时通常倾向于避免的。但我不会这么快就放弃，至少在有其他选择可以考虑的情况下不会|5241208|我们的问题的解决方案实际上非常简单，并且利用了Freezable类。这个类的主要目的是定义具有可修改和只读状态的对象，但在我们的例子中有趣的特性是，即使Freezable对象不在可视或逻辑树中，它们也可以继承DataContext。我不知道启用此行为的确切机制，但我们将利用它来使我们的绑定工作…|5241209|我们的想法是创建一个继承Freezable并声明数据依赖属性的类(我称它为BindingProxy，原因很快就会变得很明显)：|5241210|public+class+BindingProxy+:+Freezable
{
++++#region+Overrides+of+Freezable
+
++++protected+override+Freezable+CreateInstanceCore()
++++{
++++++++return+new+BindingProxy();
++++}
+
++++#endregion
+
++++public+object+Data
++++{
++++++++get+{+return+(object)GetValue(DataProperty);+}
++++++++set+{+SetValue(DataProperty,+value);+}
++++}
+
++++//+Using+a+DependencyProperty+as+the+backing+store+for+Data.++This+enables+animation,+styling,+binding,+etc...
++++public+static+readonly+DependencyProperty+DataProperty+=
++++++++DependencyProperty.Register("Data",+typeof(object),+typeof(BindingProxy),+new+UIPropertyMetadata(null));
}|5241211|然后，我们可以在DataGrid的资源中声明该类的一个实例，并将数据属性绑定到当前的DataContext：|5241212|<DataGrid.Resources>
++++<local:BindingProxy+x:Key="proxy"+Data="{Binding}"+/>
</DataGrid.Resources>|5241213|最后一步是将这个BindingProxy对象(可通过StaticResource轻松访问)指定为绑定的源：|5241214|<DataGridTextColumn+Header="Price"+Binding="{Binding+Price}"+IsReadOnly="False"
++++++++++++++++Visibility="{Binding+Data.ShowPrice,
++++++++++++++++Converter={StaticResource+visibilityConverter},
++++++++++++++++Source={StaticResource+proxy}}"/>|5241215|注意，绑定路径的前缀是“Data”，因为该路径现在是相对于BindingProxy对象的。|5241216|绑定现在可以正常工作，并且可以根据ShowPrice属性正确地显示或隐藏列。|5241217|entityMap|0|LINK|mutability|MUTABLE|url|http://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/|1^0|0|0|2|1R|0|0|H|B|1|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|29|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|2A|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|2B|8|@]|9|@$F|2C|G|2D|1|2E]]|A|$]]|$1|H|3|I|5|6|7|2F|8|@]|9|@$F|2G|G|2H|1|2I]]|A|$]]|$1|J|3|K|5|6|7|2J|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|2K|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|2L|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|2M|8|@]|9|@]|A|$]]|$1|R|3|S|5|T|7|2N|8|@]|9|@]|A|$U|V]]|$1|W|3|X|5|6|7|2O|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|2P|8|@]|9|@]|A|$]]|$1|Z|3|10|5|11|7|2Q|8|@]|9|@]|A|$]]|$1|12|3|-4|5|6|7|2R|8|@]|9|@]|A|$]]|$1|13|3|14|5|6|7|2S|8|@]|9|@]|A|$]]|$1|15|3|-4|5|6|7|2T|8|@]|9|@]|A|$]]|$1|16|3|17|5|6|7|2U|8|@]|9|@]|A|$]]|$1|18|3|19|5|T|7|2V|8|@]|9|@]|A|$U|V]]|$1|1A|3|1B|5|6|7|2W|8|@]|9|@]|A|$]]|$1|1C|3|1D|5|T|7|2X|8|@]|9|@]|A|$U|V]]|$1|1E|3|1F|5|6|7|2Y|8|@]|9|@]|A|$]]|$1|1G|3|1H|5|6|7|2Z|8|@]|9|@]|A|$]]|$1|1I|3|1J|5|6|7|30|8|@]|9|@]|A|$]]|$1|1K|3|1L|5|6|7|31|8|@]|9|@]|A|$]]|$1|1M|3|1N|5|T|7|32|8|@]|9|@]|A|$U|V]]|$1|1O|3|1P|5|6|7|33|8|@]|9|@]|A|$]]|$1|1Q|3|1R|5|T|7|34|8|@]|9|@]|A|$U|V]]|$1|1S|3|1T|5|6|7|35|8|@]|9|@]|A|$]]|$1|1U|3|1V|5|T|7|36|8|@]|9|@]|A|$U|V]]|$1|1W|3|1X|5|6|7|37|8|@]|9|@]|A|$]]|$1|1Y|3|1Z|5|6|7|38|8|@]|9|@]|A|$]]|$1|20|3|-4|5|6|7|39|8|@]|9|@]|A|$]]]|21|$22|$5|23|24|25|A|$26|27]]|28|$5|23|24|25|A|$26|27]]]]

If an element is not part of the visual tree, then RelativeSource will never work.
In this case, you need to try a different technique, pioneered by Thomas Levesque.
He has the solution on his blog under <a href="http://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/" rel="noreferrer">[WPF] How to bind to data when the DataContext is not inherited</a>. And it works absolutely brilliantly!
In the unlikely event that his blog is down, Appendix A contains a mirror copy of <a href="http://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/" rel="noreferrer">his article</a>.
Please do not comment here, please <a href="http://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/" rel="noreferrer">comment directly on his blog post</a>.
<h1>Appendix A: Mirror of blog post</h1>
The DataContext property in WPF is extremely handy, because it is automatically inherited by all children of the element where you assign it; therefore you don’t need to set it again on each element you want to bind. However, in some cases the DataContext is not accessible: it happens for elements that are not part of the visual or logical tree. It can be very difficult then to bind a property on those elements…
Let’s illustrate with a simple example: we want to display a list of products in a DataGrid. In the grid, we want to be able to show or hide the Price column, based on the value of a ShowPrice property exposed by the ViewModel. The obvious approach is to bind the Visibility of the column to the ShowPrice property:
<pre><code>&lt;DataGridTextColumn Header=&quot;Price&quot; Binding=&quot;{Binding Price}&quot; IsReadOnly=&quot;False&quot;
 Visibility=&quot;{Binding ShowPrice,
 Converter={StaticResource visibilityConverter}}&quot;/&gt;
</code></pre>
Unfortunately, changing the value of ShowPrice has no effect, and the column is always visible… why? If we look at the Output window in Visual Studio, we notice the following line:
<blockquote>
System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=ShowPrice; DataItem=null; target element is ‘DataGridTextColumn’ (HashCode=32685253); target property is ‘Visibility’ (type ‘Visibility’)
The message is rather cryptic, but the meaning is actually quite simple: WPF doesn’t know which FrameworkElement to use to get the DataContext, because the column doesn’t belong to the visual or logical tree of the DataGrid.
</blockquote>
We can try to tweak the binding to get the desired result, for instance by setting the RelativeSource to the DataGrid itself:
<pre><code>&lt;DataGridTextColumn Header=&quot;Price&quot; Binding=&quot;{Binding Price}&quot; IsReadOnly=&quot;False&quot;
 Visibility=&quot;{Binding DataContext.ShowPrice,
 Converter={StaticResource visibilityConverter},
 RelativeSource={RelativeSource FindAncestor, AncestorType=DataGrid}}&quot;/&gt;
</code></pre>
Or we can add a CheckBox bound to ShowPrice, and try to bind the column visibility to the IsChecked property by specifying the element name:
<pre><code>&lt;DataGridTextColumn Header=&quot;Price&quot; Binding=&quot;{Binding Price}&quot; IsReadOnly=&quot;False&quot;
 Visibility=&quot;{Binding IsChecked,
 Converter={StaticResource visibilityConverter},
 ElementName=chkShowPrice}&quot;/&gt;
</code></pre>
But none of these workarounds seems to work, we always get the same result…
At this point, it seems that the only viable approach would be to change the column visibility in code-behind, which we usually prefer to avoid when using the MVVM pattern… But I’m not going to give up so soon, at least not while there are other options to consider 
The solution to our problem is actually quite simple, and takes advantage of the Freezable class. The primary purpose of this class is to define objects that have a modifiable and a read-only state, but the interesting feature in our case is that Freezable objects can inherit the DataContext even when they’re not in the visual or logical tree. I don’t know the exact mechanism that enables this behavior, but we’re going to take advantage of it to make our binding work…
The idea is to create a class (I called it BindingProxy for reasons that should become obvious very soon) that inherits Freezable and declares a Data dependency property:
<pre><code>public class BindingProxy : Freezable
{
 #region Overrides of Freezable
 
 protected override Freezable CreateInstanceCore()
 {
 return new BindingProxy();
 }
 
 #endregion
 
 public object Data
 {
 get { return (object)GetValue(DataProperty); }
 set { SetValue(DataProperty, value); }
 }
 
 // Using a DependencyProperty as the backing store for Data. This enables animation, styling, binding, etc...
 public static readonly DependencyProperty DataProperty =
 DependencyProperty.Register(&quot;Data&quot;, typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null));
}
</code></pre>
We can then declare an instance of this class in the resources of the DataGrid, and bind the Data property to the current DataContext:
<pre><code>&lt;DataGrid.Resources&gt;
 &lt;local:BindingProxy x:Key=&quot;proxy&quot; Data=&quot;{Binding}&quot; /&gt;
&lt;/DataGrid.Resources&gt;
</code></pre>
The last step is to specify this BindingProxy object (easily accessible with StaticResource) as the Source for the binding:
<pre><code>&lt;DataGridTextColumn Header=&quot;Price&quot; Binding=&quot;{Binding Price}&quot; IsReadOnly=&quot;False&quot;
 Visibility=&quot;{Binding Data.ShowPrice,
 Converter={StaticResource visibilityConverter},
 Source={StaticResource proxy}}&quot;/&gt;
</code></pre>
Note that the binding path has been prefixed with “Data”, since the path is now relative to the BindingProxy object.
The binding now works correctly, and the column is properly shown or hidden based on the ShowPrice property.

blocks|key|5241297|text|我在不断更新我对绑定的研究。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|5241298|原始Here|5241299|DataContext|5241300|DataContext是包含在FrameworkElement中的DependencyProperty。|5241301|PresentationFramework.dll|CODE|5241302|namespace+System.Windows
{
++++public+class+FrameworkElement+:+UIElement
++++{
++++++++public+static+readonly+DependencyProperty+DataContextProperty;
++++++++public+object+DataContext+{+get;+set;+}
++++}
}|code-block|syntax|javascript|5241303|而且，WPF中的所有UI控件都继承FrameworkElement类。|5241304|5241305|在学习绑定或DataContext时，您不必更深入地学习FrameworkElement。|blockquote|5241306|5241307|但是，这里要简要提到一个事实，即可以包含所有UI控件的最接近的对象是FrameworkElement。|5241308|DataContext始终是绑定的参考点。|5241309|绑定可以直接调用从最近的DataContext开始的DataContext类型格式的值。|5241310|<TextBlock+Text="{Binding}"+DataContext="James"/>|5241311|绑定到Text="{Binding}"的值直接从最近的DataContext+TextBlock传递。|5241312|因此，Text的绑定结果值为'James‘。|5241313|5241314|Type整数|unordered-list-item|5241315|5241316|当直接从Xaml向DataContext赋值时，资源定义首先对于值类型是必需的。由于所有字符串都被识别为String.|5241317|Using系统mscrolib，因此标准不支持简单类型变量类型。|ordered-list-item|5241318|5241319|你可以用任何单词来定义它，但主要使用sys单词。|5241320|xmlns:sys="clr-namespace:System;assembly=mscorlib“|5241321|xaml中的|5241322|Create+YEAR资源键以StaticResource.|5241323|的形式声明要创建的类型的值|5241324|+2020++...|5241325|值的|5241326|All类型|5241327|5241328|值类型直接绑定到DataContext的情况很少。|5241329|因为我们要绑定一个对象。|5241330|+true+++...+|5241331|5241332|Another类型|5241333|5241334|不仅可以使用字符串，还可以使用各种类型。因为DataContext是一种对象类型。|5241335|终于..。|5241336|在WPF中使用绑定时，大多数开发人员并没有充分意识到DataContext的存在、功能和重要性。|5241337|这可能意味着绑定是靠运气联系在一起的。|5241338|5241339|+特别是如果您负责或参与一个大型的WPF项目，您应该更清楚地了解应用程序的DataContext层次结构。此外，在没有这种DataContext概念的情况下引入WPF的各种流行的MVVM框架系统，将在自由实现功能方面造成更大的限制。+|5241340|5241341|5241342|绑定|5241343|查找祖先Binding|5241344|Element+Binding|5241345|
|5241346|MultiBinding|5241347|5241348|Self属性绑定|5241349|5241350|Find祖先Binding|5241351|5241352|TemplatedParent+Binding|5241353|5241354|Static属性绑定|5241355|5241356|DataContext绑定|5241357|string+property|5241358|<TextBox+Text="{Binding+Keywords}"/>|5241359|​|5241360|元素绑定|5241361|<CheckBox+x:Name="usingEmail"/>
<TextBlock+Text="{Binding+ElementName=usingEmail,+Path=IsChecked}"/>|5241362|5241363|5241364|<TextBlock+Margin="5,2"+Text="This+disappears+as+the+control+gets+focus...">
++<TextBlock.Visibility>
++++++<MultiBinding+Converter="{StaticResource+TextInputToVisibilityConverter}">
++++++++++<Binding+ElementName="txtUserEntry2"+Path="Text.IsEmpty"+/>
++++++++++<Binding+ElementName="txtUserEntry2"+Path="IsFocused"+/>
++++++</MultiBinding>
++</TextBlock.Visibility>
</TextBlock>|5241365|5241366|自身属性绑定|5241367|<TextBlock+x:Name="txt"+Text="{Binding+ElementName=txt,+Path=Tag}"/>|5241368|如果你必须绑定你自己的属性，你可以使用Self+Property+Binding而不是Element+Binding。|5241369|你不再需要声明x:Name来绑定你自己的属性。|5241370|<TextBlock+Text="{Binding+RelativeSource={RelativeSource+Self},+Path=Tag}"/>|5241371|5241372|根据最接近的父控件查找祖先绑定导入。|5241373|<TextBlock+Text="{Binding+RelativeSource={RelativeSource+AncestorType=Window},+Path=Title}"/>|5241374|除了找到的控件的属性外，还可以使用DataContext对象中的属性(如果存在)。|5241375|<TextBlock+Text="{Binding+RelativeSource={RelativeSource+AncestorType=Window},+Path=DataContext.Email}"/>|5241376|5241377|TemplatedParent绑定|5241378|这是一个可以在ControlTemplate中使用的方法，您可以导入作为ControlTemplate所有者的控件。|5241379|<Style+TargetType="Button">
++<Setter+Property="Template">
++++++<Setter.Value>
++++++++++<ControlTemplate+TargetType="Button">
++++++++++++++<TextBlock+Text="{Binding+RelativeSource={RelativeSource+TemplatedParent},+Path=Content}"/>
++++++++++</ControlTemplate>
++++++</Setter.Value>
++</Setter>|5241380|您可以访问所有属性和DataContext。|5241381|<TextBlock+Text="{Binding+RelativeSource={RelativeSource+TemplatedParent},+Path=Content}"/>|5241382|5241383|静态属性绑定|5241384|您可以直接访问绑定属性值。|5241385|5241386|声明static属性。|5241387|5241388|namespace+Exam
{
++public+class+ExamClass
++{
++++++public+static+string+ExamText+{+get;+set;+}
++}
}+|5241389|在XAML中使用静态类的|5241390|。|5241391|5241392|<Window+...+xmlns:exam="clr-namespace:Exam">|5241393|5241394|绑定属性。|5241395|5241396|<TextBlock+Text="{Binding+exam:ExamClass.ExamText}"/>|5241397|或者，您可以像使用Converter__一样设置资源密钥。|5241398|<Window.Resource>
++<cvt:VisibilityToBooleanConverter+x:Key="VisibilityToBooleanConverter"/>
++<exam:ExamClass+x:Key="ExamClass">
</Window.Resource>
...

<TextBlock+Text="{Binding+Source={StaticResource+ExamClass},+Path=ExamText}"/>|5241399|5241400|我从未在正常情况下使用过静态属性。这是因为偏离其自身DataContext的数据可能会中断整个WPF应用程序的流程，并严重影响可读性。然而，这种方法在开发阶段以及在DataContext+(或ViewModel)中都被积极使用，以实现快速测试和功能。|5241401|5241402|5241403|坏绑定和好绑定|5241404|✔️如果要绑定的属性包含在Datacontext中，|5241405|这样你就不必使用ElementBinding了。|5241406|通过连接控制使用ElementBinding不是一个功能问题，|5241407|这是可能的，但它打破了绑定的基本模式。|5241408|绑定不佳|5241409|<TextBox+x:Name="text"+Text="{Binding+UserName}"/>
...
<TextBlock+Text="{Binding+ElementName=text,+Path=Text}"/>|5241410|良好的绑定|5241411|<TextBox+Text="{Binding+UserName}"/>
...
<TextBlock+Text="{Binding+UserName}"/>|5241412|5241413|当使用属于更高层控件的属性时，✔️不使用ElementBinding。|5241414|5241415|<Window+x:Name="win">
++<TextBlock+Text="{Binding+ElementName=win,+Path=DataContext.UserName}"/>
++...|5241416|5241417|<Window>
++<TextBlock+Text="{Binding+RelativeSource={RelativeSource+AncestorType=Window},+Path=DataContext.UserName}"/>
++...|5241418|太棒了！|5241419|<Window>
++<TextBlock+DataContext="{Binding+RelativeSource={RelativeSource+AncestorType=Window},+Path=DataContext}"+
+++++++++++++Text="{Binding+UserName}"/>
++...|5241420|5241421|在使用您自己的属性时，✔️不要使用ElementBinding。|5241422|5241423|<TextBlock+x:Name="txt"+Text="{Binding+ElementName=txt,+Path=Foreground}"/>|5241424|5241425|<TextBlock+Text="{Binding+RelativeSource={RelativeSource+Self},+Path=Foreground}"/>|5241426|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/devncore/wpf-xaml-binding^0|0|E|0|2|4|0|0|0|0|1G|0|0|P|0|0|H|G|0|0|0|0|0|0|0|0|3|G|13|9|0|3|4|0|0|0|6|0|0|0|7|8|0|0|I|3|0|0|0|7|4|0|0|0|0|0|5|0|0|0|P|0|0|C|0|1|4|7|5|0|0|0|9|0|0|0|15|0|0|5|0|0|1C|0|0|J|0|0|1|37|0|0|0|0|2|0|0|B|0|0|F|0|0|0|C|0|0|0|8|0|0|0|D|0|0|0|N|0|0|0|A|0|0|0|D|0|0|F|0|F|0|0|0|1|0|0|4|0|0|0|1|0|0|C|0|0|0|1|0|0|6|0|0|0|1N|J|L|17|F|0|0|N|7|6|0|0|0|1|0|0|I|0|0|0|15|0|0|0|1|0|0|H|0|0|1M|7|F|10|F|0|0|0|M|0|0|0|1|0|0|6|0|0|D|0|0|0|B|2|6|0|0|0|0|C|0|0|1|0|0|0|0|0|5|0|0|0|0|T|9|9|0|0|0|0|3H|0|0|0|0|7|0|0|Q|0|0|O|0|0|V|0|0|J|0|0|4|0|0|0|5|0|0|0|1|0|0|Z|0|0|4|0|0|0|5|0|0|0|4|0|0|0|1|0|0|W|0|0|4|0|0|0|5|0|0^^$0|@$1|2|3|4|5|6|7|6Y|8|@$9|6Z|A|70|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|71|8|@]|D|@$9|72|A|73|1|74]]|E|$]]|$1|H|3|I|5|6|7|75|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|76|8|@$9|77|A|78|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|79|8|@$9|7A|A|7B|B|N]]|D|@]|E|$]]|$1|O|3|P|5|Q|7|7C|8|@]|D|@]|E|$R|S]]|$1|T|3|U|5|6|7|7D|8|@$9|7E|A|7F|B|N]]|D|@]|E|$]]|$1|V|3|-4|5|6|7|7G|8|@]|D|@]|E|$]]|$1|W|3|X|5|Y|7|7H|8|@]|D|@]|E|$]]|$1|Z|3|-4|5|6|7|7I|8|@]|D|@]|E|$]]|$1|10|3|11|5|6|7|7J|8|@]|D|@]|E|$]]|$1|12|3|13|5|6|7|7K|8|@]|D|@]|E|$]]|$1|14|3|15|5|6|7|7L|8|@]|D|@]|E|$]]|$1|16|3|17|5|Q|7|7M|8|@]|D|@]|E|$R|S]]|$1|18|3|19|5|6|7|7N|8|@$9|7O|A|7P|B|N]|$9|7Q|A|7R|B|N]]|D|@]|E|$]]|$1|1A|3|1B|5|6|7|7S|8|@$9|7T|A|7U|B|N]]|D|@]|E|$]]|$1|1C|3|-4|5|6|7|7V|8|@]|D|@]|E|$]]|$1|1D|3|1E|5|1F|7|7W|8|@$9|7X|A|7Y|B|C]]|D|@]|E|$]]|$1|1G|3|-4|5|6|7|7Z|8|@]|D|@]|E|$]]|$1|1H|3|1I|5|6|7|80|8|@]|D|@]|E|$]]|$1|1J|3|1K|5|1L|7|81|8|@$9|82|A|83|B|N]]|D|@]|E|$]]|$1|1M|3|-4|5|6|7|84|8|@]|D|@]|E|$]]|$1|1N|3|1O|5|6|7|85|8|@$9|86|A|87|B|N]]|D|@]|E|$]]|$1|1P|3|1Q|5|6|7|88|8|@]|D|@]|E|$]]|$1|1R|3|1S|5|6|7|89|8|@]|D|@]|E|$]]|$1|1T|3|1U|5|1L|7|8A|8|@$9|8B|A|8C|B|N]]|D|@]|E|$]]|$1|1V|3|1W|5|6|7|8D|8|@]|D|@]|E|$]]|$1|1X|3|1Y|5|6|7|8E|8|@]|D|@]|E|$]]|$1|1Z|3|20|5|6|7|8F|8|@]|D|@]|E|$]]|$1|21|3|22|5|1F|7|8G|8|@$9|8H|A|8I|B|C]]|D|@]|E|$]]|$1|23|3|-4|5|6|7|8J|8|@]|D|@]|E|$]]|$1|24|3|25|5|6|7|8K|8|@$9|8L|A|8M|B|C]]|D|@]|E|$]]|$1|26|3|27|5|6|7|8N|8|@$9|8O|A|8P|B|C]]|D|@]|E|$]]|$1|28|3|29|5|6|7|8Q|8|@$9|8R|A|8S|B|C]|$9|8T|A|8U|B|C]]|D|@]|E|$]]|$1|2A|3|-4|5|6|7|8V|8|@]|D|@]|E|$]]|$1|2B|3|2C|5|1F|7|8W|8|@$9|8X|A|8Y|B|C]]|D|@]|E|$]]|$1|2D|3|-4|5|6|7|8Z|8|@]|D|@]|E|$]]|$1|2E|3|2F|5|6|7|90|8|@$9|91|A|92|B|C]]|D|@]|E|$]]|$1|2G|3|2H|5|6|7|93|8|@$9|94|A|95|B|C]]|D|@]|E|$]]|$1|2I|3|2J|5|6|7|96|8|@$9|97|A|98|B|C]]|D|@]|E|$]]|$1|2K|3|2L|5|6|7|99|8|@$9|9A|A|9B|B|C]]|D|@]|E|$]]|$1|2M|3|-4|5|6|7|9C|8|@]|D|@]|E|$]]|$1|2N|3|2O|5|Y|7|9D|8|@$9|9E|A|9F|B|C]]|D|@]|E|$]]|$1|2P|3|-4|5|6|7|9G|8|@]|D|@]|E|$]]|$1|2Q|3|-4|5|6|7|9H|8|@]|D|@]|E|$]]|$1|2R|3|2S|5|6|7|9I|8|@$9|9J|A|9K|B|C]]|D|@]|E|$]]|$1|2T|3|2U|5|6|7|9L|8|@$9|9M|A|9N|B|C]]|D|@]|E|$]]|$1|2V|3|2W|5|1F|7|9O|8|@$9|9P|A|9Q|B|C]]|D|@]|E|$]]|$1|2X|3|2Y|5|6|7|9R|8|@]|D|@]|E|$]]|$1|2Z|3|30|5|1F|7|9S|8|@$9|9T|A|9U|B|C]]|D|@]|E|$]]|$1|31|3|2Y|5|6|7|9V|8|@]|D|@]|E|$]]|$1|32|3|33|5|1F|7|9W|8|@$9|9X|A|9Y|B|C]]|D|@]|E|$]]|$1|34|3|2Y|5|6|7|9Z|8|@]|D|@]|E|$]]|$1|35|3|36|5|1F|7|A0|8|@$9|A1|A|A2|B|C]]|D|@]|E|$]]|$1|37|3|2Y|5|6|7|A3|8|@]|D|@]|E|$]]|$1|38|3|39|5|1F|7|A4|8|@$9|A5|A|A6|B|C]]|D|@]|E|$]]|$1|3A|3|2Y|5|6|7|A7|8|@]|D|@]|E|$]]|$1|3B|3|3C|5|1F|7|A8|8|@$9|A9|A|AA|B|C]]|D|@]|E|$]]|$1|3D|3|-4|5|6|7|AB|8|@]|D|@]|E|$]]|$1|3E|3|3F|5|6|7|AC|8|@$9|AD|A|AE|B|C]]|D|@]|E|$]]|$1|3G|3|3H|5|6|7|AF|8|@$9|AG|A|AH|B|C]|$9|AI|A|AJ|B|N]]|D|@]|E|$]]|$1|3I|3|3J|5|Q|7|AK|8|@]|D|@]|E|$R|S]]|$1|3K|3|3L|5|6|7|AL|8|@$9|AM|A|AN|B|C]]|D|@]|E|$]]|$1|3M|3|3N|5|6|7|AO|8|@$9|AP|A|AQ|B|C]]|D|@]|E|$]]|$1|3O|3|3P|5|Q|7|AR|8|@]|D|@]|E|$R|S]]|$1|3Q|3|3L|5|6|7|AS|8|@$9|AT|A|AU|B|C]]|D|@]|E|$]]|$1|3R|3|30|5|6|7|AV|8|@$9|AW|A|AX|B|C]]|D|@]|E|$]]|$1|3S|3|3T|5|Q|7|AY|8|@]|D|@]|E|$R|S]]|$1|3U|3|3L|5|6|7|AZ|8|@$9|B0|A|B1|B|C]]|D|@]|E|$]]|$1|3V|3|3W|5|6|7|B2|8|@$9|B3|A|B4|B|C]]|D|@]|E|$]]|$1|3X|3|3Y|5|Q|7|B5|8|@]|D|@]|E|$R|S]]|$1|3Z|3|40|5|6|7|B6|8|@$9|B7|A|B8|B|C]|$9|B9|A|BA|B|N]|$9|BB|A|BC|B|N]]|D|@]|E|$]]|$1|41|3|42|5|6|7|BD|8|@$9|BE|A|BF|B|C]|$9|BG|A|BH|B|N]]|D|@]|E|$]]|$1|43|3|44|5|Q|7|BI|8|@]|D|@]|E|$R|S]]|$1|45|3|3L|5|6|7|BJ|8|@$9|BK|A|BL|B|C]]|D|@]|E|$]]|$1|46|3|47|5|6|7|BM|8|@$9|BN|A|BO|B|C]]|D|@]|E|$]]|$1|48|3|49|5|Q|7|BP|8|@]|D|@]|E|$R|S]]|$1|4A|3|4B|5|6|7|BQ|8|@$9|BR|A|BS|B|C]]|D|@]|E|$]]|$1|4C|3|4D|5|Q|7|BT|8|@]|D|@]|E|$R|S]]|$1|4E|3|3L|5|6|7|BU|8|@$9|BV|A|BW|B|C]]|D|@]|E|$]]|$1|4F|3|4G|5|6|7|BX|8|@$9|BY|A|BZ|B|C]]|D|@]|E|$]]|$1|4H|3|4I|5|6|7|C0|8|@$9|C1|A|C2|B|C]|$9|C3|A|C4|B|N]|$9|C5|A|C6|B|N]]|D|@]|E|$]]|$1|4J|3|4K|5|Q|7|C7|8|@]|D|@]|E|$R|S]]|$1|4L|3|4M|5|6|7|C8|8|@$9|C9|A|CA|B|C]]|D|@]|E|$]]|$1|4N|3|4O|5|Q|7|CB|8|@]|D|@]|E|$R|S]]|$1|4P|3|3L|5|6|7|CC|8|@$9|CD|A|CE|B|C]]|D|@]|E|$]]|$1|4Q|3|4R|5|6|7|CF|8|@$9|CG|A|CH|B|C]]|D|@]|E|$]]|$1|4S|3|4T|5|6|7|CI|8|@$9|CJ|A|CK|B|C]]|D|@]|E|$]]|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I am constantly updating my research on Binding.
 Original <a href="https://github.com/devncore/wpf-xaml-binding" rel="nofollow noreferrer">Here</a>
<h2>DataContext</h2>
DataContext is the DependencyProperty included in the FrameworkElement. 
<code>PresentationFramework.dll</code>
<pre class="lang-cs prettyprint-override"><code>namespace System.Windows
{
 public class FrameworkElement : UIElement
 {
 public static readonly DependencyProperty DataContextProperty;
 public object DataContext { get; set; }
 }
}
</code></pre>
And, all UI Controls in WPF inherit the <code>FrameworkElement</code> class.
<blockquote>
At this point in learning Binding or DataContext, you don't have to study FrameworkElement in greater depth. 
However, this is to briefly mention the fact that the closest object that can encompass all UI Controls is the FrameworkElement. 
 
</blockquote>
<h3>DataContext is always the reference point for Binding.</h3>
Binding can directly recall values for the DataContext type format starting with the nearest DataContext.
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding}&quot; DataContext=&quot;James&quot;/&gt;
</code></pre>
The value bound to <code>Text=&quot;{Binding}&quot;</code> is passed directly from the nearest DataContext, <code>TextBlock</code>. 
Therefore, the Binding result value of <code>Text</code> is 'James'. 
 
<ul>
<li>Type integer 
When assigning a value to DataContext directly from Xaml, resource definitions are required first for value types such as Integer and Boolean.
Because all strings are recognized as String.
1. Using System <code>mscrolib</code> in Xaml
<blockquote>
Simple type variable type is not supported by standard. 
You can define it with any word, but mostly use <code>sys</code> words.
</blockquote>
<pre class="lang-xml prettyprint-override"><code>xmlns:sys=&quot;clr-namespace:System;assembly=mscorlib&quot;
</code></pre>
2. Create <code>YEAR</code> resource key in xaml
<blockquote>
Declare the value of the type you want to create in the form of a StaticResource.
</blockquote>
<pre class="lang-xml prettyprint-override"><code>&lt;Window.Resources&gt;
 &lt;sys:Int32 x:Key=&quot;YEAR&quot;&gt;2020&lt;/sys:Int32&gt;
&lt;/Window.Resources&gt;
...
&lt;TextBlock Text=&quot;{Binding}&quot; DataContext=&quot;{StaticResource YEAR&quot;/&gt;
</code></pre>
</li>
<li>All type of value 
There are very few cases where Value Type is binding directly into DataContext. 
Because we're going to bind an object.
<pre class="lang-xml prettyprint-override"><code>&lt;Window.Resources&gt;
 &lt;sys:Boolean x:Key=&quot;IsEnabled&quot;&gt;true&lt;/sys:Boolean&gt;
 &lt;sys:double x:Key=&quot;Price&quot;&gt;7.77&lt;/sys:double&gt;
&lt;/Window.Resources&gt;
...
&lt;StackPanel&gt;
 &lt;TextBlock Text=&quot;{Binding}&quot; DataContext=&quot;{StaticResource IsEnabled}&quot;/&gt;
 &lt;TextBlock Text=&quot;{Binding}&quot; DataContext=&quot;{StaticResource Price}&quot;/&gt;
&lt;/StackPanel&gt;
</code></pre>
</li>
<li>Another type 
Not only String but also various types are possible. Because DataContext is an object type.
 
</li>
</ul>
<h3>Finally...</h3>
In using Binding at WPF, most developers are not fully aware of the existence, function and importance of DataContext. 
It may mean that Binding is being connected by luck.
<blockquote>
Especially if you are responsible for or participating in a large WPF project, you should understand the DataContext hierarchy of the application more clearly. In addition, the introduction of WPF's various popular MVVM Framework systems without this DataContext concept will create even greater limitations in implementing functions freely.
 
</blockquote>
<hr />
<h2>Binding</h2>
<ul>
<li>DataContext Binding</li>
<li>Element Binding</li>
<li>MultiBinding</li>
<li>Self Property Binding</li>
<li>Find Ancestor Binding</li>
<li>TemplatedParent Binding</li>
<li>Static Property Binding 
 </li>
</ul>
<h3>DataContext Binding</h3>
<code>string property</code>
<pre class="lang-xml prettyprint-override"><code>&lt;TextBox Text=&quot;{Binding Keywords}&quot;/&gt;
</code></pre>
 
<h3>Element Binding</h3>
<pre class="lang-xml prettyprint-override"><code>&lt;CheckBox x:Name=&quot;usingEmail&quot;/&gt;
&lt;TextBlock Text=&quot;{Binding ElementName=usingEmail, Path=IsChecked}&quot;/&gt;
</code></pre>
 
<h3>MultiBinding</h3>
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Margin=&quot;5,2&quot; Text=&quot;This disappears as the control gets focus...&quot;&gt;
 &lt;TextBlock.Visibility&gt;
 &lt;MultiBinding Converter=&quot;{StaticResource TextInputToVisibilityConverter}&quot;&gt;
 &lt;Binding ElementName=&quot;txtUserEntry2&quot; Path=&quot;Text.IsEmpty&quot; /&gt;
 &lt;Binding ElementName=&quot;txtUserEntry2&quot; Path=&quot;IsFocused&quot; /&gt;
 &lt;/MultiBinding&gt;
 &lt;/TextBlock.Visibility&gt;
&lt;/TextBlock&gt;
</code></pre>
 
 
### Self Property Binding
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock x:Name=&quot;txt&quot; Text=&quot;{Binding ElementName=txt, Path=Tag}&quot;/&gt;
</code></pre>
If you have to bind your own property, you can use <code>Self Property Binding</code>, instead of using <code>Element Binding</code>. 
You no longer have to declare <code>x:Name</code> to bind your own property.
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource Self}, Path=Tag}&quot;/&gt;
</code></pre>
 
 
### Find Ancestor Binding
Imports based on the parent control closest to it.
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=Title}&quot;/&gt;
</code></pre>
In addition to the properties of the controls found, the properties within the DataContext object can be used if it exists.
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.Email}&quot;/&gt;
</code></pre>
 
<h3>TemplatedParent Binding</h3>
This is a method that can be used within <code>ControlTemplate</code>, and you can import the control that is the owner of the <code>ControlTemplate</code>.
<pre class="lang-xml prettyprint-override"><code>&lt;Style TargetType=&quot;Button&quot;&gt;
 &lt;Setter Property=&quot;Template&quot;&gt;
 &lt;Setter.Value&gt;
 &lt;ControlTemplate TargetType=&quot;Button&quot;&gt;
 &lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Content}&quot;/&gt;
 &lt;/ControlTemplate&gt;
 &lt;/Setter.Value&gt;
 &lt;/Setter&gt;
</code></pre>
You can access to all Property and DataContext.
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Content}&quot;/&gt;
</code></pre>
 
<h3>Static Property Binding</h3>
You can access binding property value directly.
1. Declare <code>static</code> property.
<pre class="lang-cs prettyprint-override"><code>namespace Exam
{
 public class ExamClass
 {
 public static string ExamText { get; set; }
 }
} 
</code></pre>
2. Using static class in XAML.
<pre class="lang-xml prettyprint-override"><code>&lt;Window ... xmlns:exam=&quot;clr-namespace:Exam&quot;&gt;
</code></pre>
3. Binding property.
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding exam:ExamClass.ExamText}&quot;/&gt;
</code></pre>
Or, you can set Resource key like using <code>Converter</code>.
<pre class="lang-xml prettyprint-override"><code>&lt;Window.Resource&gt;
 &lt;cvt:VisibilityToBooleanConverter x:Key=&quot;VisibilityToBooleanConverter&quot;/&gt;
 &lt;exam:ExamClass x:Key=&quot;ExamClass&quot;&gt;
&lt;/Window.Resource&gt;
...

&lt;TextBlock Text=&quot;{Binding Source={StaticResource ExamClass}, Path=ExamText}&quot;/&gt;
</code></pre>
<blockquote>
I have never used the Static Property under normal circumstances. This is because data that deviates from its own DataContext can disrupt the flow of whole WPF applications and impair readability significantly. However, this method is actively used in the development stage to implement fast testing and functions, as well as in the DataContext (or ViewModel). 
 
</blockquote>
<hr />
<h2>Bad Binding &amp; Good Binding</h2>
<h3>✔️ If the property you want to bind is included in Datacontext,       you don't have to use ElementBinding.</h3>
      Using ElementBinding through connected control is not a functional problem, 
      but it breaks the fundamental pattern of Binding.
 Bad Binding
<pre class="lang-xml prettyprint-override"><code>&lt;TextBox x:Name=&quot;text&quot; Text=&quot;{Binding UserName}&quot;/&gt;
...
&lt;TextBlock Text=&quot;{Binding ElementName=text, Path=Text}&quot;/&gt;
</code></pre>
 Good Binding
<pre class="lang-xml prettyprint-override"><code>&lt;TextBox Text=&quot;{Binding UserName}&quot;/&gt;
...
&lt;TextBlock Text=&quot;{Binding UserName}&quot;/&gt;
</code></pre>
 
<h3>✔️ Do not use ElementBinding when using property belonging to higher layers control.</h3>
 Bad Binding
<pre class="lang-xml prettyprint-override"><code>&lt;Window x:Name=&quot;win&quot;&gt;
 &lt;TextBlock Text=&quot;{Binding ElementName=win, Path=DataContext.UserName}&quot;/&gt;
 ...
</code></pre>
 Good Binding
<pre class="lang-xml prettyprint-override"><code>&lt;Window&gt;
 &lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.UserName}&quot;/&gt;
 ...
</code></pre>
 Great!
<pre class="lang-xml prettyprint-override"><code>&lt;Window&gt;
 &lt;TextBlock DataContext=&quot;{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext}&quot; 
 Text=&quot;{Binding UserName}&quot;/&gt;
 ...
</code></pre>
 
<h3>✔️ Do not use ElementBinding when using your own properties.</h3>
 Bad Binding
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock x:Name=&quot;txt&quot; Text=&quot;{Binding ElementName=txt, Path=Foreground}&quot;/&gt;
</code></pre>
 Good Binding
<pre class="lang-xml prettyprint-override"><code>&lt;TextBlock Text=&quot;{Binding RelativeSource={RelativeSource Self}, Path=Foreground}&quot;/&gt;
</code></pre>

How do I use <code>RelativeSource</code> with WPF bindings and what are the different use-cases?

问如何在RelativeSource中使用WPF绑定？
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