WPF自定义命令在上下文菜单中禁用，直到单击任何按钮 [英] WPF custom command in context menu are disabled until any button clicked

问题描述

我有一个自定义命令，我尝试从上下文菜单执行它们，但它们总是显示为禁用，除非我单击任何按钮的UI（按钮没有任何与命令有关）。

I have a custom command and I try to execute them from the context menu, but they are always displayed as disabled unless I click any button on the UI (buttons do not have anything to do with commands).

单击按钮后，命令开始正确显示（如果不可用，则会禁用并启用命令）。

After clicking a button, commands start to be displayed correctly (when they are unavailable they get disabled and enabled if available).

编辑：原来是不是按钮点击使命令正常工作，但按钮或其他控件焦点（例如，如果我选项卡到控件，这也启用我的命令）。

it turns out that it is not the button click which makes command work correctly, but button or other controls in focus (e.g. if I tab into a control this also enables my commands).

下面是命令的代码：

<Window.InputBindings>
    <KeyBinding Command="{x:Static local:MainWindow.Quit}" Key="Q" Modifiers="Ctrl"/>
    <KeyBinding Command="{x:Static local:MainWindow.Disconnect}" Key="D" Modifiers="Ctrl"/>
</Window.InputBindings>

<Window.ContextMenu>
    <ContextMenu Opacity="95">
        <MenuItem Header="Quit Application                  Ctrl + Q"   Command="{x:Static local:MainWindow.Quit}"/>
        <MenuItem Header="Disconnect from the pump   Ctrl + D" Command="{x:Static local:MainWindow.Disconnect}"/>
    </ContextMenu>
</Window.ContextMenu>

这里是命令CanExecuteMethod：

Here is the commands CanExecuteMethod:

public static RoutedCommand Quit = new RoutedCommand();   

private void QuitCanExecute(object sender, CanExecuteRoutedEventArgs e)
     {
      e.CanExecute = true;
      e.Handled = true;
     }

推荐答案

确实有一些特殊的上下文菜单作为命令的载体：
菜单不被视为窗口的一部分，因此不像它的视觉树中的一个元素。

Completely different track, now: there is indeed something special about the ContextMenu as the carrier for commands: the menu is not regarded as part of the window and therefore does not behave like an element in its visual tree would.

这里定义的问题有不同的解决方案：
http：// www .wpftutorial.net / RoutedCommandsInContextMenu.html

There are different solutions for your problems defined here: http://www.wpftutorial.net/RoutedCommandsInContextMenu.html

最简单的方法似乎是添加到您的XAML（窗口）：

The easiest approach seems to be adding this to your XAML (for the window):

FocusManager.FocusedElement="{Binding RelativeSource={x:Static RelativeSource.Self}, Mode=OneTime}"

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