将命令属性添加到任何自定义控件

Question

我可以使用以下代码导航到另一个视图。我想使用 tabControl 和自定义控件进行导航，但没有用于绑定 myCommand 的命令属性。那么如何将我的命令绑定到自定义控件？:

<Button Command="{Binding myCommand}" Content="Nav"/>

1.Is还有绑定的吗？
2.how 我可以将命令属性添加到自定义控件吗？

Answer 1

自定义控件和用户控件

为命令创建 DependencyProperty。

public class MyControl : Control
{
    static MyControl()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(MyControl), new FrameworkPropertyMetadata(typeof(MyControl)));
    }

    public ICommand Command
    {
        get { return (ICommand)GetValue(CommandProperty); }
        set { SetValue(CommandProperty, value); }
    }

    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register(
        "Command",
        typeof(ICommand),
        typeof(MyControl),
        new PropertyMetadata(null, OnCommandPropertyChanged));

    private static void OnCommandPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        MyControl control = d as MyControl;
        if (control == null) return;

        control.MouseLeftButtonDown -= OnControlLeftClick;
        control.MouseLeftButtonDown += OnControlLeftClick;
    }

    private static void OnControlLeftClick(object sender, MouseButtonEventArgs e)
    {
        MyControl control = sender as MyControl;
        if (control == null || control.Command == null) return;

        ICommand command = control.Command;

        if (command.CanExecute(null))
            command.Execute(null);
    }
}

xaml:

<local:MyControl Command="{Binding SomeCommand}"/>

其他控件

创建附加行为。

public static class ExecutesCommandOnLeftClickBehavior
{
    public static ICommand GetCommand(DependencyObject obj)
    {
        return (ICommand)obj.GetValue(CommandProperty);
    }

    public static void SetCommand(DependencyObject obj, ICommand value)
    {
        obj.SetValue(CommandProperty, value);
    }

    public static readonly DependencyProperty CommandProperty = DependencyProperty.RegisterAttached(
        "Command",
        typeof(ICommand),
        typeof(ExecutesCommandOnLeftClickBehavior),
        new PropertyMetadata(null, OnCommandPropertyChanged));

    private static void OnCommandPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        UIElement element = d as UIElement;
        if (element == null) return;

        element.MouseLeftButtonDown -= OnMouseLeftButtonDown;
        element.MouseLeftButtonDown += OnMouseLeftButtonDown;
    }

    private static void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        UIElement element = sender as UIElement;
        if (element == null) return;

        ICommand command = GetCommand(element);
        if (command == null) return;

        if (command.CanExecute(null))
            command.Execute(null);
    }
}

xaml:

<Grid local:ExecutesCommandOnLeftClickBehavior.Command="{Binding SomeCommand}"/>

您可以将事件更改为 MouseLeftButtonDown 以外的事件，如果需要，请为 CommandParameter 添加 DependencyProperty (AttachedProperty)。

Answer 2

每个 UIElement 都有所谓的 InputBindings

Input bindings support the binding of commands to input devices. For example, MouseBinding implements input bindings that include properties that are particular to mouse devices.

<Label Content="new">
    <Label.InputBindings>
        <MouseBinding Gesture="LeftClick" 
                      Command="{Binding Path=myCommand}" 
                      CommandParameter="smth"/>
    </Label.InputBindings>
</Label>

因此，与其注册新的命令和命令参数 DP 并处理事件以触发命令，不如尝试使用开箱即用的功能

Answer 3

添加到@djomlastic 的回答，以防有人想用命令发送参数。

创建新的依赖项属性,

public object CommandParameter
    {
        get { return (object)GetValue(CommandParameterProperty); }
        set { SetValue(CommandParameterProperty, value); }
    }

    public static readonly DependencyProperty CommandParameterProperty = DependencyProperty.Register(nameof(CommandParameter), typeof(object)
                                                                               , typeof(<ClassName>), new PropertyMetadata(string.Empty));

并在调用执行时将 CommandParameter 对象作为参数而不是 null 发送，

 private static void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    UIElement element = sender as UIElement;
    if (element == null) return;

    ICommand command = GetCommand(element);
    if (command == null) return;

    if (command.CanExecute(element.CommandParameter))
        command.Execute(element.CommandParameter);
}

将命令属性添加到任何自定义控件

Add command property to any custom controls

c#

wpf

mvvm

icommand

自定义控件和用户控件

其他控件

将命令 属性 添加到任何自定义控件

Add command property to any custom controls

c#

wpf

mvvm

icommand

自定义控件和用户控件

其他控件

将命令属性添加到任何自定义控件