將DoubleClick命令從DataGrid行綁定到虛擬機

Question

我有一個Datagrid，並且不喜歡我的解決方法在點擊（又名選定）行的viewmodel上觸發雙擊命令。

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> 

視圖模型：

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; 
     } 
    } 

我想在我的視圖模型擺脫視圖相關的代碼（具有依賴對象和可視樹幫手）的，因爲這會以某種方式破壞可測試性。但另一方面，這種方式避免了當用戶沒有點擊某行而是在標題上時發生了某些事情。 PS：我試着看看附加的行爲，但我無法在工作中從Skydrive下載，所以'內置'解決方案將是最好的。

Answer 1

爲什麼不簡單使用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> 

你的命令是這樣的：

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

     return mouseDoubleClickCommand; 
    } 
} 

編輯：我現在改用此的Interaction.Triggers：

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

Answer 2

您可以嘗試以下解決方法：

<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> 
    ................... 

在這種情況下，你必須在DataGrid

Answer 3

這裏每列指定DataTemplate是你可以如何使用附加的行爲實現：

編輯：現在在DataGridRow而不是DataGrid上註冊行爲，以便點擊DataGridHeader點擊或。

行爲：

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); 
     } 
    } 
} 

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> 

然後，您將需要修改MouseDoubleClickCommand刪除MouseButtonEventArgs參數，並與您的SelectedItem類型更換它。

Answer 4

的方式比任何這裏所提出的解決方案的簡單。

我正在使用這一個。

<!-- 
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> 

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