从上下文菜单中获取所选项目

Question

我正在动态创建一组图像并将它们放入堆栈面板中，如下所示：-

            Image image = new Image();
            image.Name = "image_" + iCounter;
            image.Height = 100;
            image.Width = 100;
            image.Source = bitmap;
            image.HorizontalAlignment = System.Windows.HorizontalAlignment.Left;
            image.Stretch = Stretch.Fill;
            image.VerticalAlignment = VerticalAlignment.Top;
            //image.MouseDown += new MouseButtonEventHandler(image_MouseDown);
            image.ToolTip = "Right-Click for Options";
            image.ContextMenu = GetContextMenu();

            Separator separator = new Separator();
            separator.Name = "separator_" + iCounter;

            AddImagesStackPanel.Children.Add(image);
            AddImagesStackPanel.Children.Add(separator);

            iCounter++;

然后在上下文菜单中我有以下代码：-

    private System.Windows.Controls.ContextMenu GetContextMenu()
    {
        System.Windows.Controls.MenuItem mi1;
        System.Windows.Controls.MenuItem mi2;
    
        System.Windows.Controls.ContextMenu _contextMenu = new System.Windows.Controls.ContextMenu();
    
        mi1 = new System.Windows.Controls.MenuItem();
        mi1.Header = "Show Normal Size";
        mi1.Click += new RoutedEventHandler(ContextMenuItem1_Click);

        mi2 = new System.Windows.Controls.MenuItem();
        mi2.Header = "Remove image";
        mi2.Click += new RoutedEventHandler(ContextMenuItem2_Click);

        _contextMenu.Items.Add(mi1);
        _contextMenu.Items.Add(mi2);
        return _contextMenu;
    }

现在我希望在用户右键单击图像时获取所选项目，我有这个代码：-

    private void ContextMenuItem2_Click(object sender, RoutedEventArgs e)
    {
        object obj = e.OriginalSource;

        string imageName = ((System.Windows.Controls.Image)obj).Name;
        string[] split = imageName.Split('_');
        imageUploads.RemoveAt(Convert.ToInt32(split[1]));
        DisplayImagesInStackPanel(imageUploads);
    }

但 obj 不包含图像的名称，因为它是 RoutedEventArgs。有什么方法可以在上下文菜单中获取所选项目吗？

Answer 1

在评论中讨论后，这应该可以工作：

// The binding source.
private readonly ObservableCollection<BitmapImage> _imageList = new ObservableCollection<BitmapImage>();
public ObservableCollection<BitmapImage> ImageList
{
    get { return _imageList; }
}

如何显示它并设置上下文菜单：

<ItemsControl ItemsSource="{Binding ImageList}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                <Image Source="{Binding}" Width="100" Height="100"
                       HorizontalAlignment="Left" Stretch="Fill"
                       VerticalAlignment="Top" ToolTip="Right-Click for Options">
                    <Image.ContextMenu>
                        <ContextMenu>
                            <MenuItem Header="Show Normal Size" Click="Image_CM_ShowNormalSize_Click"
                                      Tag="{Binding RelativeSource={RelativeSource AncestorType=ContextMenu}, Path=PlacementTarget}"/> <!-- The placement target is the object to which the context menu belongs, i.e. the image -->
                            <MenuItem Header="Remove Image" Click="Image_CM_RemoveImage_Click"
                                      Tag="{Binding RelativeSource={RelativeSource AncestorType=ContextMenu}, Path=PlacementTarget.DataContext}"/> <!-- The DataContext of the Image is the BitmapImage, which should be removed from the list -->
                        </ContextMenu>
                    </Image.ContextMenu>
                </Image>
                <Separator/>
            </StackPanel>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

处理程序可能是什么样子：

private void Image_CM_ShowNormalSize_Click(object sender, RoutedEventArgs e)
{
    Image img = (sender as FrameworkElement).Tag as Image;
    img.Width = (img.Source as BitmapImage).PixelWidth;
    img.Height = (img.Source as BitmapImage).PixelHeight;
}

private void Image_CM_RemoveImage_Click(object sender, RoutedEventArgs e)
{
    BitmapImage img = (sender as FrameworkElement).Tag as BitmapImage;
    // If the image is removed from the bound list the respective visual elements
    // will automatically be removed as well.
    ImageList.Remove(img);
}

Answer 2

但是 obj 不包含图像的名称，因为它是 RoutedEventArgs。

确实如此，但是此时的 obj 是一个 MenuItem，如果向下钻取一层，就可以获得图像。

有什么方法可以在上下文菜单中获取所选项目吗？

通常情况下，人们会通过菜单的 ItemSource 绑定（或者 MenuItem 如果它们是子菜单）来加载模型类（在您的情况下为图像），并且如果有人采取这种方式他们可以将原始项目从 DataContext 中拉出来，例如在我的例子中，该项目是一个 MRU 类项目。

private void SelectMRU(object sender, RoutedEventArgs e)
{
    var mru = (e.OriginalSource as MenuItem).DataContext as MRU;
    var name = mru.Name;
    ...
}

因为您是手动执行操作，所以您应该使用相关的 Image 加载 MenuItem 的 Tag 属性，

 mi1.Tag = {Image instance in question};

然后提取事件。

 var image = (e.OriginalSource as MenuItem).Tag as Image;