Wpf如何绑定祖先的viewmodel中的命令 [英] Wpf how to bind to commands in the ancestor's viewmodel

问题描述

我的英语不好，所以我不知道我是否可以说清楚，对不起。

我真的不知道如何在做一些研究时解释它。



目前，我有一个名为ToolPathPage的UserConstrol页面，它包含另一个名为ToolPathDataControl的UserControl，它只包含一个DataGrid。 />


现在我想将ToolPathPageViewModel中的Command绑定到ToolPathDataControl.xaml中的MenuItem。



我尝试过：

 <   DataGrid.ContextMenu  >  
 <   ContextMenu    >  
 <   MenuItem    标题  = 清除   命令  =   {Binding RelativeSource = {RelativeSource Mode = FindAncestor，AncestorType = {x：Type local：ToolPathPage}，AncestorLevel = 1}，Path = DataContext。（viewModel：ToolPathPageViewModel.Clear_AllCommand }}  /  >  
 <   / ContextMenu  >  
 <   / DataGrid.ContextMenu  >  
 

在输出窗口中，它显示：

无法找到绑定源，引用'RelativeSource FindAncestor，AncestorType ='mTracke r.ToolPathPage'，AncestorLevel ='1''。 BindingExpression：路径= DataContext的（0）;的DataItem = NULL; target元素是'MenuItem'（Name =''）; target属性是'Command'（类型'ICommand'）

解决方案

感谢 @ RichardDeeming ，我得到了我的最终解决方案：

 <   DataGrid    标记  =  {Binding RelativeSource = {RelativeSource Mode = FindAncestor，AncestorType = {x：Type local：ToolPathPage }，Path = DataContext。（viewModel：ToolPathPageViewModel.Clear_AllCommand）} >  
  <   DataGrid.ContextMenu  >  
 <   ContextMenu  >  
 <   MenuItem    < span class =code-attribute>标题  = 清除   命令  =  {Binding PlacementTarget.Tag，RelativeSource = {RelativeSource Mode = FindAncestor，AncestorType = ContextMenu}}  /   >  
 <   / ContextMenu  >  
 <   / DataGrid.ContextMenu  >  
 <   / DataGrid  > < /跨度> 

My English is bad, so I don't know if I can make it clear, sorry about that.
And I really don't know how to explain it when trying to do some research.

Currently, I have a page which is a UserConstrol called "ToolPathPage", and it contains another UserControl called "ToolPathDataControl" which contains nothing but a DataGrid.

Now I want to bind a Command in the ToolPathPageViewModel to a MenuItem in ToolPathDataControl.xaml.

What I have tried:

<DataGrid.ContextMenu>
    <ContextMenu >
        <MenuItem Header="Clear" Command="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type local:ToolPathPage},AncestorLevel= 1}, Path=DataContext.(viewModel:ToolPathPageViewModel.Clear_AllCommand)}"/>
    </ContextMenu>
</DataGrid.ContextMenu>

In the Output window it says:

Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='mTracker.ToolPathPage', AncestorLevel='1''. BindingExpression:Path=DataContext.(0); DataItem=null; target element is 'MenuItem' (Name=''); target property is 'Command' (type 'ICommand')

解决方案

Thanks to @RichardDeeming, I got my final solution:

<DataGrid Tag="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type local:ToolPathPage}},Path=DataContext.(viewModel:ToolPathPageViewModel.Clear_AllCommand)}">
    <DataGrid.ContextMenu>
        <ContextMenu>
            <MenuItem Header="Clear" Command="{Binding PlacementTarget.Tag,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=ContextMenu}}"/>
        </ContextMenu>
    </DataGrid.ContextMenu>
</DataGrid>

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