在XAML中设置命令目标

Question

我很难理解RoutedCommand的CommandTarget属性.

基本上,我有一些静态命令,在用户控件(而不是窗口)中有实现.我在用户控件中创建了一个命令绑定.如果我在usercontrol中声明了按钮,那么我就可以使用我的路由事件了.但是,当按钮位于usercontrol之外时,我无法使用我的路由事件.我认为命令目标将解决我的问题.

那么如何为工具栏usercontrol的按钮设置commandtarget,以便调用Container的Executed和CanExecuted？

编辑代码与micahtan更改的更改,但我仍然无法将其发送到CanExecute或Execute.

窗口XAML:

<Window x:Class="RoutedCommands.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:RoutedCommands"
    xmlns:toolbar="clr-namespace:RoutedCommands.Toolbar"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <local:Container Width="100" Height="25" x:Name="MyContainer" />
        <toolbar:Toolbar Width="100" Height="25" CommandTarget="{Binding MyContainer}" />
    </StackPanel>
</Window>

工具栏XAML:

<UserControl x:Class="RoutedCommands.Toolbar.Toolbar"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:RoutedCommands"
    x:Name="MyToolbar"
    Height="300" Width="300">
    <Grid>
        <Button Command="{x:Static local:Commands.MyCommand}" Content="Try Me" CommandTarget="{Binding ElementName=MyToolbar, Path=CommandTarget, Mode=OneWay}" />
    </Grid>
</UserControl>

工具栏CS:

    public partial class Toolbar : UserControl
    {
        public Toolbar()
        {
            InitializeComponent();
        }

        // Using a DependencyProperty as the backing store for CommandTarget.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty CommandTargetProperty =
                DependencyProperty.Register("CommandTarget", typeof(IInputElement), typeof(Toolbar), new UIPropertyMetadata(null));

        public IInputElement CommandTarget
        {
            get { return (IInputElement)GetValue(CommandTargetProperty); }
            set { SetValue(CommandTargetProperty, value); }
        }
    }

容器XAML:

<UserControl x:Class="RoutedCommands.Container"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:RoutedCommands"
    Height="300" Width="300">
    <UserControl.CommandBindings>
        <CommandBinding Command="{x:Static local:Commands.MyCommand}" CanExecute="CommandBinding_CanExecute" Executed="CommandBinding_Executed" />
    </UserControl.CommandBindings>
    <Grid>
        <Button Command="{x:Static local:Commands.MyCommand}" Content="Click Me" />
    </Grid>
</UserControl>

集装箱CS:

public partial class Container : UserControl
{
    public Container()
    {
        InitializeComponent();
    }

    private void CommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
    {
        Console.WriteLine("My Command Executed");
    }

    private void CommandBinding_CanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        Console.WriteLine("My Command Can Execute");
        e.CanExecute = true;
    }
}

RoutedCommands:

namespace RoutedCommands
{
    public static class Commands
    {
        public static readonly RoutedUICommand MyCommand = new RoutedUICommand(); 
    }
}

Answer 1

如果你想使用CommandTargets,我会在你的自定义UserControl上创建一个CommandTarget DependencyProperty,类似于它在ButtonBase上定义的方式.

完成后,将Button的CommandTarget设置为自定义UserControl的CommandTarget.

编辑:代码示例

如果您正在进行MVVM架构,Rudi的注释是有效的 - 在这种情况下,RelayCommands或其他形式的包装代理都可以正常工作.根据您的代码示例,它看起来并不像您使用的那种方法,因此我的原始评论.

至于代码,您只需要更改ToolBar类.这假设您的MyCommand类继承自RoutedUICommand.这是XAML:

<UserControl
    x:Class="WPFCommandTarget.CustomToolBar"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WPFCommandTarget"
    x:Name="theControl">
    <Grid>
        <Button
            x:Name="theButton"
            Command="{x:Static local:Commands.MyCommand}"
            CommandTarget="{Binding ElementName=theControl, Path=CommandTarget, Mode=OneWay}"
            Content="Try Me" />
    </Grid>
</UserControl>

这是代码隐藏的代码:

使用System.Windows; 使用System.Windows.Controls;

namespace WPFCommandTarget
{
    /// <summary>
    /// Interaction logic for CustomToolBar.xaml
    /// </summary>
    public partial class CustomToolBar : UserControl
    {
        public CustomToolBar()
        {
            InitializeComponent();
        }

        public IInputElement CommandTarget
        {
            get { return (IInputElement)GetValue(CommandTargetProperty); }
            set { SetValue(CommandTargetProperty, value); }
        }

        // Using a DependencyProperty as the backing store for CommandTarget.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty CommandTargetProperty =
            DependencyProperty.Register("CommandTarget", typeof(IInputElement), typeof(CustomToolBar), new UIPropertyMetadata(null));
    }
}

请注意,我已经更改了测试项目中的一些类名/命名空间.你必须改变它们以满足你的需要.