如何将命令绑定到MenuItem (WPF)?

Here is my code from the View.xaml.cs:

以下是我在视图中的代码。

private RelayCommand _closeCommand;
public ICommand CloseCommand
{
    get
    {
        if (_closeCommand == null)
        {
            _closeCommand = new RelayCommand(param => this.OnClose());
        }
        return _closeCommand;
    }
}

public void OnClose()
{
    Close();
}

And here is some code from my View.xaml:

下面是我的一些代码。

<Window.ContextMenu>
    <ContextMenu>
        <MenuItem Name="menuItem_Close" Header="Close" Command="{Binding CloseCommand}" />
    </ContextMenu> 
</Window.ContextMenu>

When I run the program and select the close menu item, nothing happens. The CloseCommand code doesn't even get executed.

当我运行程序并选择关闭菜单项时，什么也没有发生。CloseCommand代码甚至没有被执行。

3 个解决方案

#1

ContextMenu is not part of the VisualTree, that's why the DataContext will not be inherited. Here ContextMenu.PlacementTarget is some kind of relay to get the Window:

ContextMenu不是VisualTree的一部分，这就是为什么不会继承DataContext。快捷菜单。定位目标是某种获得窗口的继电器:

<MenuItem Name="menuItem_Close" Header="Close"
          Command="{Binding Path=PlacementTarget.DataContext.CloseCommand, RelativeSource={RelativeSource AncestorType=ContextMenu}}" />

#2

Old question, new answer. For me the problem was that GalaSoft.MvvmLight.Command.RelayCommand didn't support closures for the action. RelayCommand stores a weak reference to the action so a closure gets deallocated almost immediately. The action must be a model method or be retained in some other way.

老问题,新答案。对我来说，问题在于GalaSoft.MvvmLight.Command。RelayCommand不支持该操作的闭包。RelayCommand存储对操作的弱引用，以便闭包几乎立即被释放。操作必须是一个模型方法，或者以其他方式保留。

#3

-1

for binding cross visual tree, refer to

对于绑定跨视觉树，请参阅

Binding Visibility for DataGridColumn in WPF

WPF中的DataGridColumn的绑定可见性

or jsut try search BindingProxy

或者jsut尝试搜索BindingProxy

#1