c# - 将 ContextMenu 绑定(bind)到 Datagrid 列

Question

我正在尝试将 DataGrid 列标题绑定(bind)到它自己的 ContextMenu，如下所示:

 <DataGrid x:Name="AllLogs">
     <DataGrid.ContextMenu>
         <ContextMenu>
              <MenuItem Header="Show/Hide Columns" 
                        ItemsSource="{Binding ElementName=AllLogs, Path=Columns}">
                    <MenuItem.ItemTemplate>
                         <DataTemplate>
                             <TextBlock Text="{Binding Header}"></TextBlock>
                         </DataTemplate>
                    </MenuItem.ItemTemplate>
              </MenuItem>
           </ContextMenu>
       </DataGrid.ContextMenu>
   </DataGrid>

它总是在输出中发送以下错误:

Cannot find source for binding with reference 'ElementName=AllLogs'. BindingExpression:Path=Columns; DataItem=null; target element is 'MenuItem' (Name=''); target property is 'ItemsSource' (type 'IEnumerable')

---

编辑:与 ComboBox 的绑定(bind)按预期工作

 <ComboBox ItemsSource="{Binding ElementName=AllLogs, Path=Columns}">
        <ComboBox.ItemTemplate>
              <DataTemplate>
                  <CheckBox Content="{Binding Header}"/>
              </DataTemplate>
         </ComboBox.ItemTemplate>
 </ComboBox>

Answer 1

你应该先设置ContextMenu的DataContext，这样绑定(bind)到Menu Item的ItemsSource可以继承相同的DataContext。

<ContextMenu DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Show/Hide Columns" 
    ItemsSource="{Binding Columns}">
    <MenuItem.ItemTemplate>
         <DataTemplate>
              <TextBlock Text="{Binding Header}"></TextBlock>
         </DataTemplate>
    </MenuItem.ItemTemplate>
</MenuItem>
</ContextMenu>