LongListSelector and ContextMenu
本文关键字：ContextMenu and LongListSelector | 更新日期: 2023-09-27 17:59:49
当用户长按ListBoxItem:时，我使用以下代码用LongListSelector创建页面并添加ContextMenu
<Controls:LongListSelector Height="Auto" x:Name="historylist" HorizontalContentAlignment="Stretch"
Background="White" SelectionChanged="DidPressSelectItem" Hold="HoldListBox">
<Controls:LongListSelector.ItemTemplate>
<DataTemplate>
<local:SearchTemplateSelector Content="{Binding}" HorizontalContentAlignment="Stretch">
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu>
<toolkit:MenuItem Header="Remove from history" Click="DeleteVideoFromHistory"/>
<toolkit:MenuItem Header="Remove from cache" Click="DeleteVideoFromCache"/>
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
<local:SearchTemplateSelector.VideoTemplate>
<DataTemplate>
<Grid>
<Rectangle Height="1" HorizontalAlignment="Stretch" VerticalAlignment="Top" Fill="Black" Opacity="0.3" />
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Image Margin="0" Source="{Binding Path=ImgUrl}" HorizontalAlignment="Left" Width="100" Height="100" Tag="{Binding idStr}"/>
<Grid Grid.Column="1" Margin="10,0,8,0">
<Grid.RowDefinitions>
<RowDefinition Height="60"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<TextBlock Text="{Binding Name}" FontSize="20" Foreground="Black" TextWrapping="Wrap" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
<StackPanel Orientation="Horizontal" Margin="0,-5,0,0" Grid.Row="1">
<TextBlock Text="Views: " FontSize="20" Foreground="Black"/>
<TextBlock Text="{Binding ViewCount}" FontSize="20" Foreground="Black"/>
</StackPanel>
<Grid Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding TimeStr}" FontSize="20" Foreground="Black" Margin="0,0,0,0" />
</Grid>
</Grid>
</Grid>
</Grid>
</DataTemplate>
</local:SearchTemplateSelector.VideoTemplate>
<local:SearchTemplateSelector.VideoTemplateCached>
<DataTemplate>
<Grid>
<Rectangle Height="1" HorizontalAlignment="Stretch" VerticalAlignment="Top" Fill="Black" Opacity="0.3" />
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Image Margin="0" Source="{Binding Path=ImgUrl}" HorizontalAlignment="Left" Width="100" Height="100" Tag="{Binding idStr}"/>
<Grid Grid.Column="1" Margin="10,0,8,0">
<Grid.RowDefinitions>
<RowDefinition Height="60"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<TextBlock Text="{Binding Name}" FontSize="20" Foreground="Black" TextWrapping="Wrap" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
<StackPanel Orientation="Horizontal" Margin="0,-5,0,0" Grid.Row="1">
<TextBlock Text="Views: " FontSize="20" Foreground="Black"/>
<TextBlock Text="{Binding ViewCount}" FontSize="20" Foreground="Black"/>
</StackPanel>
<Grid Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding TimeStr}" FontSize="20" Foreground="Black" Margin="0,0,0,0" />
<TextBlock Text="Cached" FontSize="20" Foreground="Red" Margin="50,0,0,0" Grid.Column="1" />
</Grid>
</Grid>
</Grid>
</Grid>
</DataTemplate>
</local:SearchTemplateSelector.VideoTemplateCached>
</local:SearchTemplateSelector>
</DataTemplate>
</Controls:LongListSelector.ItemTemplate>
</Controls:LongListSelector>
这就是DeleteVideoFromHistory方法：
private void DeleteVideoFromHistory(object sender, RoutedEventArgs e)
{
VideoItem video = (sender as MenuItem).DataContext as VideoItem;
if (video == null) { return; }
historyRep.RemoveFromHistory(video);
this.RelodeTableData();
}
问题是，当我在和项目上长按并单击ContextMenu中的一个项目，然后在另一个列表框上再次按下时，我会得到最后一个VideoItem，而不是我刚刚按下的当前VideoItem。知道怎么修吗？
我也遇到过这个问题，并通过在ContextMenu的Unload上清除DataContext来解决它。
private void ContextMenu_Unload(object sender, RoutedEventArgs e)
{
ContextMenu conmen = (sender as ContextMenu);
conmen.ClearValue(FrameworkElement.DataContextProperty);
}