blocks|key|2930721|text|在ViewModel中可以非常轻松地处理此转换。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2930722|这是拥有ViewModel的巨大优势之一--您可以拥有易于测试的逻辑，例如单元之间的转换，这与用户界面代码完全分开。|2930723|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|$]]

This conversion can be handled very easily in the ViewModel. 

This is one of the huge advantages of having a ViewModel - you can have easily testable logic, such as conversion between units, which stays completely separate from the user interface code.

blocks|key|1029153|text|我建议您使用DataBinding的Coverter属性并使用XAML来解决它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1029154|DataBinding+=+{+Binding+Path+=+YourProperty,Converter+=+{StaticResource+YourConverter}}|code-block|syntax|javascript|1029155|YourConverter必须实现IValueConverter接口(msdn+doc)并且必须声明为资源。|offset|length|1029156|我更喜欢这种方法，因为将转换逻辑放在View端。|1029157|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/library/system.windows.data.ivalueconverter.aspx^0|0|0|Z|8|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]]|$1|G|3|H|5|6|7|W|8|@]|9|@$I|X|J|Y|1|Z]]|A|$]]|$1|K|3|L|5|6|7|10|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

I suggest you to use it Coverter Property of DataBinding and resolve it by XAML.

<pre><code>DataBinding = { Binding Path = YourProperty,Converter = {StaticResource YourConverter}}
</code></pre>

YourConverter must implement the IValueConverter inferface (<a href="http://msdn.microsoft.com/library/system.windows.data.ivalueconverter.aspx" rel="nofollow">msdn doc</a>) and has to be declare as Resource. 

I would prefer this approach because keep the conversion logic on the View Side.

blocks|key|2645744|text|我假设我们在WPF中。使用Binding+Converter并创建一个实现IValueConverter的对象，执行适当的配置转换。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2645745|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.windows.data.binding.converter.aspx^0|D|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

I'm supposing we are in WPF. Use a <a href="http://msdn.microsoft.com/en-us/library/system.windows.data.binding.converter.aspx" rel="nofollow">Binding Converter</a> and create an object implementing IValueConverter doing the proper configured conversion.

blocks|key|1029262|text|我能解释的最好的方法就是使用一个自定义的转换器接口。我不会继续讲下去，而是给你举个例子。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1029263|++++private+IConverter<Double,+Double>+weightConverter+=+new+KgToLbsConverter();
++++private+double+_weight;
++++public+double+Weight
++++{
++++++++get
++++++++{
++++++++++++return+weightConverter.ConvertFrom(_weight);
++++++++}

++++++++set
++++++++{
++++++++++++_weight+=+weightConverter.ConvertTo(value);
++++++++++++RaisePropertyChanged(()+=>+Weight);
++++++++}
++++}

++++///+<summary>
++++///+Provides+a+simple+converter+contract.
++++///+</summary>
++++///+<typeparam+name="T">The+source+Type</typeparam>
++++///+<typeparam+name="R">The+target+Type.</typeparam>
++++public+interface+IConverter<T,+R>
++++{
++++++++R+ConvertFrom(T+value);
++++++++T+ConvertTo(R+value);
++++}

++++///+<summary>
++++///+Provides+a+converter+to+change+Kg+to+Lbs+and+vice+versa
++++///+</summary>
++++public+class+KgToLbsConverter+:+IConverter<Double,+Double>
++++{
++++++++///+<summary>
++++++++///+From+Kg+to+Lbs.
++++++++///+</summary>
++++++++///+<param+name="value">The+weight+in+Kg.</param>
++++++++///+<returns>The+weight+in+Lbs.</returns>
++++++++public+double+ConvertFrom(double+value)
++++++++{
++++++++++++return+value+/+2.2;
++++++++}

++++++++///+<summary>
++++++++///+From+Lbs+to+Kg.
++++++++///+</summary>
++++++++///+<param+name="value">The+weight+in+Lbs.</param>
++++++++///+<returns>The+weight+in+Kg.</returns>
++++++++public+double+ConvertTo(double+value)
++++++++{
++++++++++++return+value+*+2.2;
++++++++}
++++}|code-block|syntax|javascript|1029264|使用这个，你可以制作任何你想要的转换器，然后让用户从具体的实现中进行选择。|1029265|注意:相对于转换器，我更喜欢这种模式的原因是视图模型可能需要知道什么转换模式是活动的，以及如何使用它们，这增加了相当多的灵活性。当您需要对V-VM关系进行单一转换时，IValueConverter是可行的方法，但对于您的场景，这更易于维护和扩展。|1029266|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]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The best way I can explain to do this is to use a custom converter interface. Instead of talking on I'll just zap you an example.

<pre><code> private IConverter&lt;Double, Double&gt; weightConverter = new KgToLbsConverter();
 private double _weight;
 public double Weight
 {
 get
 {
 return weightConverter.ConvertFrom(_weight);
 }

 set
 {
 _weight = weightConverter.ConvertTo(value);
 RaisePropertyChanged(() =&gt; Weight);
 }
 }

 /// &lt;summary&gt;
 /// Provides a simple converter contract.
 /// &lt;/summary&gt;
 /// &lt;typeparam name="T"&gt;The source Type&lt;/typeparam&gt;
 /// &lt;typeparam name="R"&gt;The target Type.&lt;/typeparam&gt;
 public interface IConverter&lt;T, R&gt;
 {
 R ConvertFrom(T value);
 T ConvertTo(R value);
 }

 /// &lt;summary&gt;
 /// Provides a converter to change Kg to Lbs and vice versa
 /// &lt;/summary&gt;
 public class KgToLbsConverter : IConverter&lt;Double, Double&gt;
 {
 /// &lt;summary&gt;
 /// From Kg to Lbs.
 /// &lt;/summary&gt;
 /// &lt;param name="value"&gt;The weight in Kg.&lt;/param&gt;
 /// &lt;returns&gt;The weight in Lbs.&lt;/returns&gt;
 public double ConvertFrom(double value)
 {
 return value / 2.2;
 }

 /// &lt;summary&gt;
 /// From Lbs to Kg.
 /// &lt;/summary&gt;
 /// &lt;param name="value"&gt;The weight in Lbs.&lt;/param&gt;
 /// &lt;returns&gt;The weight in Kg.&lt;/returns&gt;
 public double ConvertTo(double value)
 {
 return value * 2.2;
 }
 }
</code></pre>

Using this you could make can any converters you want, and then let the user select from concrete implementations.

Note: The reason I prefer this over converters is view models may need to know what conversion mode is active and how to work with them, this adds quite a bit of flexibility. When you need a single conversion for a V-VM relationship then IValueConverter is the way to go, but for your scenario, this is easier to maintain and to extend.

I am building an app that can track weight. I allow the user to select their unit preference of kg or lbs. I want to keep the data in the DB standard (kg) so if the user selects lbs as their preference I need the data converted from kg to lbs in the UI.

Converting values (kg to lbs) in MVVM pattern

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我正在构建一个可以跟踪体重的应用程序。我允许用户选择他们的单位首选项kg或lbs。我希望将数据保存在DB标准( kg )中，因此如果用户选择lbs作为他们的首选项，我需要在UI中将数据从kg转换为lbs。

问在MVVM模式中转换值(kg到lbs)
EN

回答 4

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在MVVM模式中转换值(kg到lbs)EN

回答 4

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在MVVM模式中转换值(kg到lbs)
EN