自定义命令不工作 [英] Custom command not working

问题描述

在我的XAML我有这样的：

In my XAML I have this:

<UserControl.CommandBindings>
    <CommandBinding Command="Help"
   CanExecute="HelpCanExecute"
   Executed="HelpExecuted" />
</UserControl.CommandBindings>

<MenuItem Header="Help" Command="Help" />

这工作得很好。所以，当我点击右键菜单，HelpExecuted（）被调用。

This works fine. So when I click the context menu, HelpExecuted() gets called.

现在我想再次做同样的，除非使用帮助命令的自定义命令。所以，我做的是：

Now I want to do the same again except use a custom command instead of the Help command. So what I do is:

public RoutedCommand MyCustomCommand = new RoutedCommand();

和改变我的XAML为：

and change my XAML to:

<UserControl.CommandBindings>
    <CommandBinding Command="MyCustomCommand"
   CanExecute="HelpCanExecute"
   Executed="HelpExecuted" />
</UserControl.CommandBindings>

<MenuItem Header="Help" Command="MyCustomCommand" />

但我得到的错误：无法在属性字符串转换MyCustomCommand''命令'，以类型的对象System.Windows.Input.ICommand。 CommandConverter不能从System.String转换。

But i get the error: Cannot convert string 'MyCustomCommand' in attribute 'Command' to object of type 'System.Windows.Input.ICommand'. CommandConverter cannot convert from System.String.

我在想什么吗？而且请注意，我想要做的这一切在XAML，即不希望使用CommandBindings.Add（新的CommandBinding（MyCustomCommand ....

What am I missing here? And please note that I want to do it all in XAML, i.e. don't want to use CommandBindings.Add(new CommandBinding(MyCustomCommand....

推荐答案

哎呀，不好意思，有点快后我原来的答复。我现在看到，这个问题是不是与类型，但用的CommandBinding。你需要使用一个标记扩展来解决命令名称。我通常让我的命令，静中有他们的声明是这样的：

Oops, sorry, was a bit fast to post my original answer. I now see that the problem is not with the type but with the CommandBinding. You need to use a markup extension to resolve the command name. I usually make my commands static in their declaration like this:

namespace MyApp.Commands
{
    public class MyApplicationCommands
    {
        public static RoutedUICommand MyCustomCommand 
                               = new RoutedUICommand("My custom command", 
                                                     "MyCustomCommand", 
                                                     typeof(MyApplicationCommands));
    }
}

而在XAML：

And in the XAML:

<UserControl x:Class="..."
             ...
             xmlns:commands="clr-namespace:MyApp.Commands">
...
<UserControl.CommandBindings>
    <CommandBinding Command="{x:Static commands:MyApplicationCommands.MyCustomCommand}"
    CanExecute="HelpCanExecute"
    Executed="HelpExecuted" />
</UserControl.CommandBindings>

您需要使用的xmlns把包含类的命名空间。我把它叫做在我上面的例子'命令'。

You need to bring in the namespace of the containing class by using xmlns. I called it 'commands' in my example above.

下面的原帖：

尝试更改命令RoutedUICommand的类型。构造函数是一个有点不同：

Try changing the type of the command to RoutedUICommand. The constructor is a bit different:

public RoutedUICommand MyCustomCommand 
             = new RoutedUICommand("Description", "Name", typeof(ContainingClass));

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