wpf eventsetter 处理程序绑定样式 [英] wpf eventsetter handler binding in style

问题描述

我有一个样式，我想用 RelativeSource 将命令绑定到 EventSetter 的 Handler.该命令在 viewModel 中.

I have a style, and I want to bind a command to the EventSetter's Handler with RelativeSource. The command is in the viewModel.

<Style x:Key="ItemTextBlockEventSetterStyle" TargetType="{x:Type TextBlock}">
    <EventSetter Event="MouseLeftButtonDown" 
                 Handler="{Binding TextBlockMouseLeftButtonDownCommand, 
                           RelativeSource={RelativeSource Self}}"/>
</Style>

问题是我得到了一个错误，因为这有问题(也许不可能以如此简单的方式做到这一点)

The problem is that I get an error, because something is wrong with this (maybe it's not possible to do this in such easy way)

我之前在谷歌上搜索了很多，我找到了 AttachedCommandBehaviour，但我认为它不适用于样式.

I've googled a lot before, and I found the AttachedCommandBehaviour, but I think it doesn't work with style.

您能否就如何解决此问题提供一些提示?

Could you give some hints on how to solve this problem?

13/10/2011 更新

我在 MVVM Light Toolkit EventToCommand 示例程序中找到了这个:

I found this in the MVVM Light Toolkit EventToCommand example program:

        <Button Background="{Binding Brushes.Brush1}"
            Margin="10"
            Style="{StaticResource ButtonStyle}"
            Content="Simple Command"
            Grid.Row="1"
            ToolTipService.ToolTip="Click to activate command">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="Click">
                <cmd:EventToCommand Command="{Binding SimpleCommand}" />
            </i:EventTrigger>
            <i:EventTrigger EventName="MouseLeave">
                <cmd:EventToCommand Command="{Binding ResetCommand}" />
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </Button>

但是在这里，绑定不在样式中.我怎样才能把这个 EventToCommand 放到按钮的样式中?

But here, the binding isn't in the style. How can I put this EventToCommand to the style of the button?

推荐答案

现在您正在将 MouseLeftButtonDown 事件绑定到 TextBlock.TextBlockMouseLeftButtonDownCommand.TextBlockMouseLeftButtonDownCommand 不是 TextBlock 的有效属性，听起来也不像是一个事件处理程序.

Right now you are binding the MouseLeftButtonDown Event to TextBlock.TextBlockMouseLeftButtonDownCommand. TextBlockMouseLeftButtonDownCommand is not a valid property for a TextBlock, nor does it sound like it's an Event Handler.

我一直在样式中使用 AttachedCommandBehavior用于将命令连接到事件.语法通常如下所示(注意命令绑定中的 DataContext):

I use the AttachedCommandBehavior all the time in styles for hooking up a Command to an Event. The syntax usually looks like this (note the DataContextin the Command Binding):

<Style x:Key="ItemTextBlockEventSetterStyle" TargetType="{x:Type TextBlock}">
    <Setter Property="local:CommandBehavior.Event" Value="MouseLeftButtonDown" />
    <Setter Property="local:CommandBehavior.Command"
            Value="{Binding DataContext.TextBlockMouseLeftButtonDownCommand, 
                            RelativeSource={RelativeSource Self}}" />
</Style>

另一种方法是将 EventSetter 与代码隐藏中的事件挂钩，并从那里处理命令:

The alternative is to hook the EventSetter up to an event in the code-behind, and process the command from there:

<Style x:Key="ItemTextBlockEventSetterStyle" TargetType="{x:Type TextBlock}">
    <EventSetter Event="MouseLeftButtonDown" 
                 Handler="TextBlockMouseLeftButtonDown"/>
</Style>

隐藏代码中的事件处理程序...

Event handler in code behind...

void TextBlockMouseLeftButtonDown(object sender, MouseEventArgs e)
{
    var tb = sender as TextBlock;
    if (tb != null)
    {
        MyViewModel vm = tb.DataContext as MyViewModel;

        if (vm != null && TextBlockMouseLeftButtonDownCommand != null
            && TextBlockMouseLeftButtonDownCommand.CanExecute(null))
        {
            vm.TextBlockMouseLeftButtonDownCommand.Execute(null)
        }
    }
}

这篇关于wpf eventsetter 处理程序绑定样式的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！