如何在mvvm中绑定moused双击命令

Question

我有listview,当有人双击任何位置时,我想要显示新窗口.但我有mvvm应用程序,我不希望在xaml文件的代码后面有任何函数,如下所示:如何绑定一个Command来双击DataGrid中的一行以及许多其他样本.我想在viewmodel文件中有方法并将其绑定如下:

<ListView ... MouseDoubleClick="{Binding myfunction}"> 

谢谢

Answer 1

这是根据列表中单击的项触发命令(在ViewModel中)的方法的工作示例.ViewModel中的命令将获取"clicked"项作为其参数.

我正在使用Textblock.InputBindings,它可能是Blachshma链接的Blend SDK的一部分,但您不需要任何其他DLL来实现此功能.

在我的示例中,ViewModel绑定到UserControl的DataContext,这就是我需要使用RelativeSource FindAncestor从我的TextBlock中查找ViewModel的原因.

编辑:通过结合固定宽度问题宽度的的的TextBlock到ActualWidth的所述的列表框.

只有一个问题,双击只有在文本块中的文本内部单击时才会起作用,即使列表本身更宽.

    <ListView ItemsSource="{Binding Model.TablesView}"   Grid.Row="1" 
              SelectedItem="{Binding Model.SelectedTable, Mode=TwoWay}"  >
        <ListView.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Path=.}" 
                   Width="{Binding Path=ActualWidth, 
                             RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListView}}}" >
                    <TextBlock.InputBindings>
                        <MouseBinding MouseAction="LeftDoubleClick" Command="{Binding DataContext.MoveItemRightCommand,
                                        RelativeSource={RelativeSource FindAncestor, 
                                        AncestorType={x:Type UserControl}}}"
                                      CommandParameter="{Binding .}"/>
                    </TextBlock.InputBindings>
                </TextBlock>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

Answer 2

您可以使用附加属性绑定所需的任何事件.

用于MouseDoubleClick:

namespace Behavior
{
public class MouseDoubleClick
{
    public static DependencyProperty CommandProperty =
        DependencyProperty.RegisterAttached("Command",
        typeof(ICommand),
        typeof(MouseDoubleClick),
        new UIPropertyMetadata(CommandChanged));

    public static DependencyProperty CommandParameterProperty =
        DependencyProperty.RegisterAttached("CommandParameter",
                                            typeof(object),
                                            typeof(MouseDoubleClick),
                                            new UIPropertyMetadata(null));

    public static void SetCommand(DependencyObject target, ICommand value)
    {
        target.SetValue(CommandProperty, value);
    }

    public static void SetCommandParameter(DependencyObject target, object value)
    {
        target.SetValue(CommandParameterProperty, value);
    }
    public static object GetCommandParameter(DependencyObject target)
    {
        return target.GetValue(CommandParameterProperty);
    }
    private static void CommandChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
    {
        Control control = target as Control;
        if (control != null)
        {
            if ((e.NewValue != null) && (e.OldValue == null))
            {
                control.MouseDoubleClick += OnMouseDoubleClick;
            }
            else if ((e.NewValue == null) && (e.OldValue != null))
            {
                control.MouseDoubleClick -= OnMouseDoubleClick;
            }
        }
    }
    private static void OnMouseDoubleClick(object sender, RoutedEventArgs e)
    {
        Control control = sender as Control;
        ICommand command = (ICommand)control.GetValue(CommandProperty);
        object commandParameter = control.GetValue(CommandParameterProperty);
        command.Execute(commandParameter);
    }
}
}

而在Xaml:

 <ListBox Behavior:MouseDoubleClick.Command="{Binding ....}"
          Behavior:MouseDoubleClick.CommandParameter="{Binding ....}"/>

Answer 3

最简单的方法是使用System.Windows.Interactivity和Microsoft.Expression.Interactions(通过Blend SDK免费提供)

首先,在视图中添加以下命名空间

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"

接下来,捕获DoubleClick事件并将其传递给命令:

<ListView ..... >
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="MouseDoubleClick">
            <local:EventToCommand Command="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=DataContext.myfunction}" />
         </i:EventTrigger
    </i:Interaction.Triggers>
</ListView>

注意:EventToCommand使用的是MVVM Light Toolkit中的一个,可以在这里下载.它的作用是在myFunction触发事件后立即执行command().

这是基于myFunction命令在ListView用户的DataContext中的假设.否则,将EventToCommand的绑定修改为命令所在的位置.