WPF:显示GridView项目的上下文菜单

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我有以下几点GridView

<ListView Name="TrackListView" ItemContainerStyle="{StaticResource itemstyle}">
    <ListView.View>
        <GridView>
            <GridViewColumn Header="Title" Width="100" HeaderTemplate="{StaticResource BlueHeader}" DisplayMemberBinding="{Binding Name}"/>
            <GridViewColumn Header="Artist" Width="100" HeaderTemplate="{StaticResource BlueHeader}" DisplayMemberBinding="{Binding Album.Artist.Name}" />
            <GridViewColumn Header="Album" Width="100" HeaderTemplate="{StaticResource BlueHeader}" DisplayMemberBinding="{Binding Album.Name}"/>
            <GridViewColumn Header="Length" Width="100" HeaderTemplate="{StaticResource BlueHeader}"/>
        </GridView>
     </ListView.View>
</ListView>

现在我想在右键单击一个有界项目时显示一个上下文菜单,这将允许我在后面的代码中处理事件时检索选定的项目。

我可以通过什么方式实现这一目标?

遵循Dennis Roche的代码,我现在有这样的:

    <ListView Name="TrackListView" ItemContainerStyle="{StaticResource itemstyle}">
        <ListView.ItemContainerStyle>
            <Style TargetType="{x:Type ListViewItem}">
                <EventSetter Event="PreviewMouseLeftButtonDown" Handler="OnListViewItem_PreviewMouseLeftButtonDown" />
                <Setter Property="ContextMenu">
                    <Setter.Value>
                        <ContextMenu>
                            <MenuItem Header="Add to Playlist"></MenuItem>
                        </ContextMenu>
                     </Setter.Value>
                </Setter>
            </Style>
        </ListView.ItemContainerStyle>

        <ListView.View>
            <GridView>
                <GridViewColumn Header="Title" Width="100" HeaderTemplate="{StaticResource BlueHeader}" DisplayMemberBinding="{Binding Name}"/>
                <GridViewColumn Header="Artist" Width="100" HeaderTemplate="{StaticResource BlueHeader}" DisplayMemberBinding="{Binding Album.Artist.Name}" />
                <GridViewColumn Header="Album" Width="100" HeaderTemplate="{StaticResource BlueHeader}" DisplayMemberBinding="{Binding Album.Name}"/>
                <GridViewColumn Header="Length" Width="100" HeaderTemplate="{StaticResource BlueHeader}"/>
            </GridView>
         </ListView.View>
    </ListView>

但跑步时,我收到了这个例外:

无法将类型'System.Windows.Controls.ContextMenu'的内容添加到'System.Object'类型的对象。标记文件'MusicRepo_Importer; component / controls / trackgridcontrol.xaml'中的对象'System.Windows.Controls.ContextMenu'出错。

问题是什么?

提问于
用户回答回答于

是的,在上下文菜单中添加一个ListView.ItemContainerStyle。

<ListView>
  <ListView.Resources>
    <ContextMenu x:Key="ItemContextMenu">
      ...
    </ContextMenu>
  </ListView.Resources>
  <ListView.ItemContainerStyle>
    <Style TargetType="{x:Type ListViewItem}">
      <EventSetter Event="PreviewMouseLeftButtonDown" Handler="OnListViewItem_PreviewMouseLeftButtonDown" />
      <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}"/>
    </Style>
  </ListView.ItemContainerStyle>
</ListView>

注意:您需要引用ContextMenu作为资源,并且无法在本地定义它。

这将启用整个行的上下文菜单。:)

另请参阅我处理PreviewMouseLeftButtonDown事件,以便确保项目已聚焦(并且在查询ListView时是当前选定的项目)。我发现当改变应用程序之间的焦点时,我不得不这样做,这可能不适用于你的情况。

在代码隐藏文件中,您需要逐步查看可视化树来查找列表容器项目,因为事件的原始源可以是项目模板的一个元素(例如堆栈面板)。

void OnListViewItem_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
  if (e.Handled)
    return;

  ListViewItem item = MyVisualTreeHelper.FindParent<ListViewItem>((DependencyObject)e.OriginalSource);
  if (item == null)
    return;

  if (item.Focusable && !item.IsFocused)
    item.Focus();
}

MyVisualTreeHelper是使用我已经写了快速走可视化树的包装。子集发布在下面。

public static class MyVisualTreeHelper
{
  static bool AlwaysTrue<T>(T obj) { return true; }

  /// <summary>
  /// Finds a parent of a given item on the visual tree. If the element is a ContentElement or FrameworkElement 
  /// it will use the logical tree to jump the gap.
  /// If not matching item can be found, a null reference is returned.
  /// </summary>
  /// <typeparam name="T">The type of the element to be found</typeparam>
  /// <param name="child">A direct or indirect child of the wanted item.</param>
  /// <returns>The first parent item that matches the submitted type parameter. If not matching item can be found, a null reference is returned.</returns>
  public static T FindParent<T>(DependencyObject child) where T : DependencyObject
  {
    return FindParent<T>(child, AlwaysTrue<T>);
  }

  public static T FindParent<T>(DependencyObject child, Predicate<T> predicate) where T : DependencyObject
  {
    DependencyObject parent = GetParent(child);
    if (parent == null)
      return null;

    // check if the parent matches the type and predicate we're looking for
    if ((parent is T) && (predicate((T)parent)))
      return parent as T;
    else
      return FindParent<T>(parent);
  }

  static DependencyObject GetParent(DependencyObject child)
  {
    DependencyObject parent = null;
    if (child is Visual || child is Visual3D)
      parent = VisualTreeHelper.GetParent(child);

    // if fails to find a parent via the visual tree, try to logical tree.
    return parent ?? LogicalTreeHelper.GetParent(child);
  }
}
用户回答回答于

喜欢这个例子,但是我没有发现你的Visual Tree Helper需要...

   <ListView.Resources>
    <ContextMenu x:Key="ItemContextMenu">
        <MenuItem x:Name="menuItem_CopyUsername"
                  Click="menuItem_CopyUsername_Click"
                  Header="Copy Username">
            <MenuItem.Icon>
                <Image Source="/mypgm;component/Images/Copy.png" />
            </MenuItem.Icon>
        </MenuItem>
        <MenuItem x:Name="menuItem_CopyPassword"
                  Click="menuItem_CopyPassword_Click"
                  Header="Copy Password">
            <MenuItem.Icon>
                <Image Source="/mypgm;component/Images/addclip.png" />
            </MenuItem.Icon>
        </MenuItem>
        <Separator />
        <MenuItem x:Name="menuItem_DeleteCreds"
                  Click="menuItem_DeleteCreds_Click"
                  Header="Delete">
            <MenuItem.Icon>
                <Image Source="/mypgm;component/Images/Delete.png" />
            </MenuItem.Icon>
        </MenuItem>
    </ContextMenu>
</ListView.Resources>
<ListView.ItemContainerStyle>
    <Style TargetType="{x:Type ListViewItem}">
        <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}" />
    </Style>
</ListView.ItemContainerStyle>

然后在MenuItem_Click事件中,我添加了如下所示的代码:

private void menuItem_CopyUsername_Click(object sender, RoutedEventArgs e)
{
    Clipboard.SetText(mySelectedItem.Username);
}

在ListView.SelectedItem上使用mySelectedItem:

 <ListView x:Name="ListViewCreds" SelectedItem="{Binding mySelectedItem, UpdateSourceTrigger=PropertyChanged}" ....

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