将 DoubleClick 命令从 DataGrid Row 绑定到 VM [英] Bind DoubleClick Command from DataGrid Row to VM

问题描述

我有一个 Datagrid 并且不喜欢我的解决方法在我的视图模型上为单击的(也称为选定的)行触发双击命令.

I have a Datagrid and don't like my workaround to fire a double click command on my viewmodel for the clicked (aka selected) row.

查看:

   <DataGrid  EnableRowVirtualization="True"
              ItemsSource="{Binding SearchItems}"
              SelectedItem="{Binding SelectedItem}"
              SelectionMode="Single"
              SelectionUnit="FullRow">

        <i:Interaction.Triggers>
            <i:EventTrigger EventName="MouseDoubleClick">
                <cmd:EventToCommand Command="{Binding MouseDoubleClickCommand}" PassEventArgsToCommand="True" />
            </i:EventTrigger>
        </i:Interaction.Triggers>
        ...
  </DataGrid>

视图模型:

    public ICommand MouseDoubleClickCommand
    {
        get
        {
            if (mouseDoubleClickCommand == null)
            {
                mouseDoubleClickCommand = new RelayCommand<MouseButtonEventArgs>(
                    args =>
                    {
                        var sender = args.OriginalSource as DependencyObject;
                        if (sender == null)
                        {
                            return;
                        }
                        var ancestor = VisualTreeHelpers.FindAncestor<DataGridRow>(sender);
                        if (ancestor != null)
                        {
                            MessengerInstance.Send(new FindDetailsMessage(this, SelectedItem.Name, false));
                        }
                    }
                    );
            }
            return mouseDoubleClickCommand;
        }
    }

我想在我的视图模型中摆脱与视图相关的代码(具有依赖对象和可视化树助手的代码)，因为这会以某种方式破坏可测试性.但另一方面，通过这种方式，我避免了当用户没有点击行而是点击标题时发生的事情.

I want to get rid of the view related code (the one with the dependency object and the visual tree helper) in my view model, as this breaks testability somehow. But on the other hand this way I avoid that something happens when the user doesn't click on a row but on the header for example.

PS:我尝试查看附加行为，但我无法在工作时从 Skydrive 下载，因此最好使用内置"解决方案.

PS: I tried having a look at attached behaviors, but I cannot download from Skydrive at work, so a 'built in' solution would be best.

推荐答案

为什么不简单地使用 CommandParameter?

Why don't you simply use the CommandParameter?

<DataGrid x:Name="myGrd"
          ItemsSource="{Binding SearchItems}"
          SelectedItem="{Binding SelectedItem}"
          SelectionMode="Single"
          SelectionUnit="FullRow">

    <i:Interaction.Triggers>
        <i:EventTrigger EventName="MouseDoubleClick">
            <cmd:EventToCommand Command="{Binding MouseDoubleClickCommand}"  
                                CommandParameter="{Binding ElementName=myGrd, Path=SelectedItem}" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
    ...
</DataGrid>

你的命令是这样的:

public ICommand MouseDoubleClickCommand
{
    get
    {
        if (mouseDoubleClickCommand == null)
        {
            mouseDoubleClickCommand = new RelayCommand<SearchItem>(
                item =>
                {
                    var selectedItem = item;
                });
        }

        return mouseDoubleClickCommand;
    }
}

我现在用它代替 Interaction.Triggers:

<DataGrid.InputBindings>
    <MouseBinding MouseAction="LeftDoubleClick"
                  Command="{Binding Path=MouseDoubleClickCommand}"
                  CommandParameter="{Binding ElementName=myGrd, Path=SelectedItem}" />
</DataGrid.InputBindings>

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