将后代对象作为命令参数传递 [英] Pass descendant object as command parameter

问题描述

你好！所以我正在使用MVVM架构模式创建一个WPF应用程序。在这个应用程序里面我有一个listview。我已经使用这段XAML代码将窗口的SizeChanged事件绑定到命令：

< i：EventTrigger EventName =SizeChanged> 
< i：InvokeCommandAction Command ={Binding WindowSizeChangedCommand}/> 
< / i：EventTrigger> 

现在，我想要的是传递给这个命令一个参数，这是列表视图宽度。



我尝试通过以下代码：

< i：EventTrigger EventName =SizeChanged> 
< i：InvokeCommandAction Command ={Binding WindowSizeChangedCommand}CommandParameter ={Binding Width，ElementName = listView}/> 
< / i：EventTrigger> 

事情是它不起作用！ Hhahahahaha我知道如何用XAML找到一个祖先对象。但我不知道如何做相反的事情。任何想法该怎么办？非常感谢你的时间！



我的尝试：

< pre>< i：EventTrigger EventName =SizeChanged> 
< i：InvokeCommandAction Command ={Binding WindowSizeChangedCommand}CommandParameter ={Binding Width，ElementName = listView}/> 
< / i：EventTrigger> 

解决方案

< i：EventTrigger EventName =SizeChanged > 
< i：InvokeCommandAction Command ={Binding WindowSizeChangedCommand}CommandParameter ={Binding ElementName = listView，Path = ActualWidth}/> 
< / i：EventTrigger> 

  public  RelayCommand WindowSizeChangedCommand 
 {
  get  
 {
  if （WindowSizeChangedCommand ==  null ）
 WindowSizeChangedCommand =  new  RelayCommand（ param = >  WidowSizeChanged（param））; 
 
  return  WindowSizeChangedCommand; 
} 
} 
 
  public   void  WindowSizeChanged（  object  param）
 {
  int  width = Convert.ToInt32（param）; 
} 

我尝试了这个确切的代码，将事件触发器置于< window>下标签，它适用于我。

Hello ! So i am creating a WPF application using the MVVM architectural pattern. Inside this application i have a listview. I have binded the SizeChanged event of the window to a command using this piece of XAML code:

<i:EventTrigger EventName="SizeChanged">
            <i:InvokeCommandAction Command="{Binding WindowSizeChangedCommand}"/>
        </i:EventTrigger>

Now, what i want is to pass to this command a parameter, which is the listview width.

I tried to to this by the following code:

<i:EventTrigger EventName="SizeChanged">
            <i:InvokeCommandAction Command="{Binding WindowSizeChangedCommand}" CommandParameter="{Binding Width, ElementName=listView}"/>
        </i:EventTrigger>

The thing is that it doesn't work ! Hhahahahaha I know how to find an ancestor object with XAML. But i don't know how to do the opposite. Any ideas what to do ?? THank you very much for your time !

What I have tried:

<pre><i:EventTrigger EventName="SizeChanged">
            <i:InvokeCommandAction Command="{Binding WindowSizeChangedCommand}" CommandParameter="{Binding Width, ElementName=listView}"/>
        </i:EventTrigger>

解决方案

<i:EventTrigger EventName="SizeChanged">
            <i:InvokeCommandAction Command="{Binding WindowSizeChangedCommand}" CommandParameter="{Binding ElementName=listView, Path=ActualWidth}"/>
        </i:EventTrigger>

public RelayCommand WindowSizeChangedCommand
{
    get
    {
        if (WindowSizeChangedCommand == null)
                WindowSizeChangedCommand = new RelayCommand(param => WidowSizeChanged(param));

            return WindowSizeChangedCommand;
    }
}

public void WindowSizeChanged(object param)
{
    int width = Convert.ToInt32(param);
}

I tried this exact code putting the event trigger under the <window> tag, and it works for me.

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