在MVC中连接事件处理程序的MVVM方式 [英] MVVM way to wire up event handlers in Silverlight

问题描述

在Silverlight / WPF中使用MVVM模式，如何连线事件处理程序？我试图将XAML 单击属性绑定到视图模型中的代理，但无法使其正常工作。

换句话说，我想替换：

  ; Button Content =Test ClickClick =Button_Click/> 
  

其中Button_Click是：

  private void Button_Click（object sender，RoutedEventArgs e）
 {
 // ... 
} 
  

与此：

 < Button Content =测试点击click ={Binding ViewModel.HandleClick}/> 
  

其中HandleClick是处理程序。尝试这会抛出一个运行时异常：

类型System.Windows.Data.Binding的对象不能转换为类型'System.Windows .RoutedEventHandler'。

解决方案

MVVM的方法是使用命令和< a href =http://msdn.microsoft.com/en-us/library/system.windows.input.icommand.aspx =nofollow> ICommand 接口。
按钮控件有一个名为的属性命令，它接收一个类型为的对象ICommand

常用的 ICommand 的实现是 Prism's DelegateCommand 。要使用它，您可以在视图模型中执行此操作：

  public class ViewModel 
 {
 public ICommand DoSomethingCommand {get;私人集合} 
 
 public ViewModel（）
 {
 DoSomethingCommand = new DelegateCommand（HandleDoSomethingCommand）; 
} 
 
 private void HandleDoSomethingCommand（）
 {
 //做东西
} 
} 
  

然后在XAML中：

  Button Content =Test ClickCommand = {Binding DoSomethingCommand} /> 
  

另外，请确保将viewmodel设置为视图的DataContext。一种方法是在您的视图的代码隐藏中：

  this.DataContext = new ViewModel（）; 
  

如果您想了解有关MVVM的更多信息，这篇文章是一个很好的起点。

Using an MVVM pattern in Silverlight/WPF, how do you wire up event handers? I'm trying to bind the XAML Click property to a delegate in the view model, but can't get it to work.

In other words, I want to replace this:

<Button Content="Test Click" Click="Button_Click" />

where Button_Click is:

private void Button_Click(object sender, RoutedEventArgs e) 
{ 
    // ...
}

with this:

<Button Content="Test Click" Click="{Binding ViewModel.HandleClick}" />

where HandleClick is the handler. Attempting this throws a runtime exception:

Object of type 'System.Windows.Data.Binding' cannot be converted to type 'System.Windows.RoutedEventHandler'.

解决方案

The MVVM way to do so is by using commands and the ICommand interface. The Button control has a property named Command which receives an object of type ICommand

A commonly used implementation of ICommand is Prism's DelegateCommand. To use it, you can do this in your view model:

public class ViewModel
{
    public ICommand DoSomethingCommand { get; private set; }

    public ViewModel()
    {
        DoSomethingCommand = new DelegateCommand(HandleDoSomethingCommand);
    }

    private void HandleDoSomethingCommand()
    {
        // Do stuff
    }
}

Then in XAML:

<Button Content="Test Click" Command={Binding DoSomethingCommand} />

Also, make sure that the viewmodel is set as your view's DataContext. One way to do so is in your view's code-behind:

this.DataContext = new ViewModel();

This article is a good place to start if you want to know more about MVVM.

这篇关于在MVC中连接事件处理程序的MVVM方式的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！