Question

我有一个Datagrid，并且不喜欢我的解决方法，在我的viewmodel上为单击的（也就是选定的）行发出双击命令。

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;
        }
    }

我希望在我的视图模型中删除与视图相关的代码（具有依赖项对象和可视树帮助器的代码），因为这会以某种方式破坏可测试性。但另一方面，这样我就可以避免当用户没有点击一行而是点击标题时会发生某些事情。

PS：我试过看一下附加行为，但是我无法在工作中从Skydrive下载，所以“内置”解决方案最好。

Answer 1

为什么不简单地使用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>

您的命令是这样的：

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

        return mouseDoubleClickCommand;
    }
}

编辑：我现在使用此代替Interaction.Triggers：

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

Answer 2

以下是使用附加行为实现它的方法：

编辑：现在在DataGridRow而不是DataGrid注册行为，以便忽略DataGridHeader次点击。

<强>行为：

public class Behaviours
{
    public static DependencyProperty DoubleClickCommandProperty =
       DependencyProperty.RegisterAttached("DoubleClickCommand", typeof(ICommand), typeof(Behaviours),
                                           new PropertyMetadata(DoubleClick_PropertyChanged));

    public static void SetDoubleClickCommand(UIElement element, ICommand value)
    {
        element.SetValue(DoubleClickCommandProperty, value);
    }

    public static ICommand GetDoubleClickCommand(UIElement element)
    {
        return (ICommand)element.GetValue(DoubleClickCommandProperty);
    }

    private static void DoubleClick_PropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var row = d as DataGridRow;
        if (row == null) return;

        if (e.NewValue != null)
        {
            row.AddHandler(DataGridRow.MouseDoubleClickEvent, new RoutedEventHandler(DataGrid_MouseDoubleClick));
        }
        else
        {
            row.RemoveHandler(DataGridRow.MouseDoubleClickEvent, new RoutedEventHandler(DataGrid_MouseDoubleClick));
        }
    }

    private static void DataGrid_MouseDoubleClick(object sender, RoutedEventArgs e)
    {
        var row= sender as DataGridRow;

        if (row!= null)
        {
            var cmd = GetDoubleClickCommand(row);
            if (cmd.CanExecute(row.Item))
                cmd.Execute(row.Item);
        }
    }
}

<强>的Xaml：

    <DataGrid x:Name="grid" EnableRowVirtualization="True"
          SelectedItem="{Binding SelectedItem}"
          SelectionMode="Single"
          SelectionUnit="FullRow" ItemsSource="{Binding SearchItems}">
       <DataGrid.RowStyle>
           <Style TargetType="DataGridRow">
                <Setter Property="Behaviours.DoubleClickCommand" Value="{Binding ElementName=grid, Path=DataContext.SortStateCommand}"/>
           </Style>
       </DataGrid.RowStyle>

然后，您需要修改MouseDoubleClickCommand以删除MouseButtonEventArgs参数，并将其替换为您的SelectedItem类型。

Answer 3

比这里提出的任何解决方案都简单。

我正在使用这个。

<!-- 
requires IsSynchronizedWithCurrentItem
for more info on virtualization/perf https://stackoverflow.com/questions/9949358/datagrid-row-virtualization-display-issue 
 -->
        <DataGrid ItemsSource="{Binding SearchItems}" 
                  IsSynchronizedWithCurrentItem="True"
                  AutoGenerateColumns="false" CanUserAddRows="False" CanUserDeleteRows="False" IsReadOnly="True" EnableRowVirtualization="True"
                  >

            <!-- for details on ICollection view (the magic behind {Binding Accounts/} https://marlongrech.wordpress.com/2008/11/22/icollectionview-explained/ -->

            <DataGrid.InputBindings>
                <MouseBinding
                    MouseAction="LeftDoubleClick"
                    Command="{Binding MouseDoubleClickCommand}"
                    CommandParameter="{Binding SearchItems/}" />
            </DataGrid.InputBindings>
        </DataGrid>

来自WPF DataGrid: CommandBinding to a double click instead of using Events

Answer 4

您可以尝试以下解决方法：

<DataGrid  EnableRowVirtualization="True"
          ItemsSource="{Binding SearchItems}"
          SelectedItem="{Binding SelectedItem}"
          SelectionMode="Single"
          SelectionUnit="FullRow">
    <DataGrid.Columns>
        <DataGridTemplateColumn Header=".....">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                        <TextBlock .....>
                            <i:Interaction.Triggers>
                                <i:EventTrigger EventName="MouseDoubleClick">
                                    <cmd:EventToCommand Command="{Binding MouseDoubleClickCommand}" PassEventArgsToCommand="True" />
                                </i:EventTrigger>
                            </i:Interaction.Triggers>
                        </TextBlock>
                </DataTemplate>
    ...................

在这种情况下，您必须为DataTemplate

中的每一列指定DataGrid

将DoubleClick命令从DataGrid行绑定到VM

4 个答案: