blocks|key|1802631|text|我和Shawn+(上图)也有同样的问题。这种方法对于POST来说可能很好，但是对于GET来说它真的很糟糕。因此，我实现了一个简单的Html扩展，它可以删除隐藏字段。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1802632|public+static+MvcHtmlString+BasicCheckBoxFor<T>(this+HtmlHelper<T>+html,+
++++++++++++++++++++++++++++++++++++++++++++++++Expression<Func<T,+bool>>+expression,
++++++++++++++++++++++++++++++++++++++++++++++++object+htmlAttributes+=+null)
{
++++var+result+=+html.CheckBoxFor(expression).ToString();
++++const+string+pattern+=+@"<input+name=""[%5E""]%2B""+type=""hidden""+value=""false""+/>";
++++var+single+=+Regex.Replace(result,+pattern,+"");
++++return+MvcHtmlString.Create(single);
}|code-block|syntax|javascript|1802633|我现在遇到的问题是，我不希望对MVC框架的更改破坏我的代码。所以我必须确保我有测试覆盖率来解释这个新合同。|1802634|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I had the same problem as Shawn (above). This approach might be great for POST, but it really sucks for GET. Therefore I implemented a simple Html extension that just whips out the hidden field.

<pre><code>public static MvcHtmlString BasicCheckBoxFor&lt;T&gt;(this HtmlHelper&lt;T&gt; html, 
 Expression&lt;Func&lt;T, bool&gt;&gt; expression,
 object htmlAttributes = null)
{
 var result = html.CheckBoxFor(expression).ToString();
 const string pattern = @"&lt;input name=""[^""]+"" type=""hidden"" value=""false"" /&gt;";
 var single = Regex.Replace(result, pattern, "");
 return MvcHtmlString.Create(single);
}
</code></pre>

The problem I now have is that I don't want a change to the MVC framework to break my code. So I have to ensure I have test coverage explaining this new contract.

blocks|key|1802688|text|附加输入标记的Here+is+the+source+code。微软非常友好地包含了针对这一点的评论。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1802689|if+(inputType+==+InputType.CheckBox)
{
++++//+Render+an+additional+<input+type="hidden".../>+for+checkboxes.+This
++++//+addresses+scenarios+where+unchecked+checkboxes+are+not+sent+in+the+request.
++++//+Sending+a+hidden+input+makes+it+possible+to+know+that+the+checkbox+was+present
++++//+on+the+page+when+the+request+was+submitted.
++++StringBuilder+inputItemBuilder+=+new+StringBuilder();
++++inputItemBuilder.Append(tagBuilder.ToString(TagRenderMode.SelfClosing));

++++TagBuilder+hiddenInput+=+new+TagBuilder("input");
++++hiddenInput.MergeAttribute("type",+HtmlHelper.GetInputTypeString(InputType.Hidden));
++++hiddenInput.MergeAttribute("name",+fullName);
++++hiddenInput.MergeAttribute("value",+"false");
++++inputItemBuilder.Append(hiddenInput.ToString(TagRenderMode.SelfClosing));
++++return+MvcHtmlString.Create(inputItemBuilder.ToString());
}|code-block|syntax|javascript|1802690|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/ASP-NET-MVC/aspnetwebstack/blob/master/src/System.Web.Mvc/Html/InputExtensions.cs#L560-L563^0|7|N|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<a href="https://github.com/ASP-NET-MVC/aspnetwebstack/blob/master/src/System.Web.Mvc/Html/InputExtensions.cs#L560-L563" rel="nofollow noreferrer">Here is the source code</a> for the additional input tag. Microsoft was kind enough to include comments that address this precisely.

<pre class="lang-cs prettyprint-override"><code>if (inputType == InputType.CheckBox)
{
 // Render an additional &lt;input type="hidden".../&gt; for checkboxes. This
 // addresses scenarios where unchecked checkboxes are not sent in the request.
 // Sending a hidden input makes it possible to know that the checkbox was present
 // on the page when the request was submitted.
 StringBuilder inputItemBuilder = new StringBuilder();
 inputItemBuilder.Append(tagBuilder.ToString(TagRenderMode.SelfClosing));

 TagBuilder hiddenInput = new TagBuilder("input");
 hiddenInput.MergeAttribute("type", HtmlHelper.GetInputTypeString(InputType.Hidden));
 hiddenInput.MergeAttribute("name", fullName);
 hiddenInput.MergeAttribute("value", "false");
 inputItemBuilder.Append(hiddenInput.ToString(TagRenderMode.SelfClosing));
 return MvcHtmlString.Create(inputItemBuilder.ToString());
}
</code></pre>

blocks|key|1802751|text|我认为最简单的解决方案是直接呈现输入元素，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1802752|<input+type="checkbox"+
+++++++id="<%25=Html.IdFor(i+=>+i.ReceiveRSVPNotifications)%25>"
+++++++name="<%25=Html.NameFor(i+=>+i.ReceiveRSVPNotifications)%25>"
+++++++value="true"
+++++++checked="<%25=Model.ReceiveRSVPNotifications+?+"checked"+:+String.Empty+%25>"+/>|code-block|syntax|javascript|1802753|在Razor语法中，这甚至更简单，因为当给出一个'true‘服务器端值时，'checked’属性直接呈现为一个"checked“值。|1802754|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I think that the simplest solution is to render the INPUT element directly as follows:

<pre><code>&lt;input type="checkbox" 
 id="&lt;%=Html.IdFor(i =&gt; i.ReceiveRSVPNotifications)%&gt;"
 name="&lt;%=Html.NameFor(i =&gt; i.ReceiveRSVPNotifications)%&gt;"
 value="true"
 checked="&lt;%=Model.ReceiveRSVPNotifications ? "checked" : String.Empty %&gt;" /&gt;
</code></pre>

In Razor syntax it is even easier, because the 'checked' attribute is directly rendered with a "checked" value when given a 'true' server-side value.

In my ASP.NET MVC app, I am rendering a checkbox using the following code:

<pre><code>&lt;%= Html.CheckBoxFor(i=&gt;i.ReceiveRSVPNotifications) %&gt;
</code></pre>

Now, I see that this renders both the checkbox input tag and a hidden input tag. The problem that I am having is when I try retrieve the value from the checkbox using the FormCollection:

<pre><code>FormValues["ReceiveRSVPNotifications"]
</code></pre>

I get the value "true,false". When looking at the rendered HTML, I can see the following:

<pre><code> &lt;input id="ReceiveRSVPNotifications" name="ReceiveRSVPNotifications" value="true" type="checkbox"&gt;
 &lt;input name="ReceiveRSVPNotifications" value="false" type="hidden"&gt;
</code></pre>

So the FormValues collection seems to join these two values since they have the same name.

Any Ideas?

Why does the CheckBoxFor render an additional input tag, and how can I get the value using the FormCollection?

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在我的ASP.NET MVC应用程序中，我使用以下代码呈现了一个复选框：<%= Html.CheckBoxFor(i=>i.ReceiveRSVPNotifications) %>现在，我看到这将呈现复选框输入标记和隐藏的输入标记。我遇到的问题是，当我尝试使用FormCollection从复选框中检索值时：FormVa...

问为什么CheckBoxFor呈现一个额外的input标记，以及如何使用FormCollection获取该值？
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问为什么CheckBoxFor呈现一个额外的input标记，以及如何使用FormCollection获取该值？
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