Question

我正在构建一个WPF自定义控件（注意：不用户控件）。控件的c＃代码定义如下：

using System.Windows;
using System.Windows.Controls;
using MvvmFoundation.Wpf;

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

        public AutoComp()
        {
            DownCommand = new RelayCommand(() =>
            {
                System.Diagnostics.Debug.WriteLine("Down");
            });
            PressedCommand = new RelayCommand(() =>
            {
                System.Diagnostics.Debug.WriteLine("Pressed");
            });
        }

        public RelayCommand DownCommand
        {
            get { return (RelayCommand)GetValue(DownCommandProperty); }
            set { SetValue(DownCommandProperty, value); }
        }

        public static readonly DependencyProperty DownCommandProperty =
            DependencyProperty.Register("DownCommand", typeof(RelayCommand), typeof(AutoComp), new PropertyMetadata(null));

        public RelayCommand PressedCommand
        {
            get { return (RelayCommand)GetValue(PressedCommandProperty); }
            set { SetValue(PressedCommandProperty, value); }
        }

        public static readonly DependencyProperty PressedCommandProperty =
            DependencyProperty.Register("PressedCommand", typeof(RelayCommand), typeof(AutoComp), new PropertyMetadata(null));
    }
}

我在Generic.xaml中为控件定义模板，如下所示：

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:TextBoxWithInputBinding">
    <Style TargetType="{x:Type local:AutoComp}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:AutoComp}">
                    <Border Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}"
                            >
                        <StackPanel>
                            <TextBox>
                                <TextBox.InputBindings>
                                    <KeyBinding Key="Down" Command="{TemplateBinding DownCommand}"/>
                                </TextBox.InputBindings>
                            </TextBox>
                            <Button Content="Press me" Command="{TemplateBinding PressedCommand}"/>
                        </StackPanel>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

当我按下＆＃34;按我＆＃34;按钮PressedCommand被触发（单词＆＃34; Pressed＆＃34;出现在输出窗口中 - 但是，当我输入TextBox并按下向下键时，没有任何反应。

我需要做什么才能使DownCommand发火？

Answer 1

如您所知，您应该使用通常的绑定标记替换TemplateBinding并使用{RelativeSource TemplatedParent}

<KeyBinding Key="Down"
    Command="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=DownCommand}"/>

我仍然想知道为什么Button绑定与TemplateBinding配合使用但TextBox KeyBinding不支持？

因为TemplateBinding已经过优化，并且与使用普通Binding相比有一些限制。例如，它只能直接在ControlTemplates的可视树中使用，而不能在DataTrigger和KeyBinding中使用。

您可以在此处找到有关此内容的更多信息：

WPF TemplateBinding vs RelativeSource TemplatedParent

Answer 2

所以我找到了答案：我需要定期绑定而不是TemplateBinding：我替换了

<KeyBinding Key="Down" Command="{TemplateBinding DownCommand}"/>

与

<KeyBinding Key="Down"
    Command="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=DownCommand}"/>

我仍然想知道为什么Button绑定适用于TemplateBinding，但TextBox KeyBinding却没有!!!

WPF KeyBinding命令不在自定义控件中触发

2 个答案: