Windows 8实用窍门系列：16.Windows 8的右键菜单

　　在Windows 8中的控件中有TextBox等输入控件的ContextMenuOpening事件和Button等非输入控件的RightTapped事件。

　　本文中将讲述者两个事件的用法。这两个事件的

　　PopupMenu是右键弹出菜单的具体类。

　　首先我们看具体菜单类的实例化和获取项目代码

        /// <summary>
        /// 设置右键点击点击具体处理细节
        /// </summary>
        /// <param name="sender"></param>
        public async void SetRightClick(object sender)
        {
            //增加菜单
            PopupMenu menu = new PopupMenu();
            menu.Commands.Add(new UICommand("复制0", null, 0));
            menu.Commands.Add(new UICommand("剪切1", null, 1));
            menu.Commands.Add(new UICommand("粘贴2", null, 2));
            menu.Commands.Add(new UICommandSeparator());
            menu.Commands.Add(new UICommand("Full Screen", null, 3));
            menu.Commands.Add(new UICommand("Snap Screen", null, 4));
            //获取选择的菜单项
            var cmd = await menu.ShowForSelectionAsync(GetRectPosition((FrameworkElement)sender));
            if (cmd != null)
            {
                switch ((int)cmd.Id)
                {
                    case 0:
                        tbText.Text = "选择了（" + cmd.Label + "） ,其ID为" + cmd.Id;
                        break;
                    case 1:
                        tbText.Text = "选择了（" + cmd.Label + "）,其ID为" + cmd.Id;
                        break;
                    case 2:
                        tbText.Text = "选择了（" + cmd.Label + "） ,其ID为" + cmd.Id;
                        break;
                    case 3:
                        tbText.Text = "选择了（" + cmd.Label + "） ,其ID为" + cmd.Id;
                        break;
                    case 4:
                        tbText.Text = "选择了（" + cmd.Label + "） ,其ID为" + cmd.Id;
                        break;
                }
            }
            else
            {
                tbText.Text = "上下文菜单";
            }
        }
        //获取菜单位置
        Rect GetRectPosition(FrameworkElement element)
        {
            GeneralTransform btnform = element.TransformToVisual(null);
            Point point = btnform.TransformPoint(new Point());
            return new Rect(point, new Size(element.ActualWidth, element.ActualHeight));
        }

　　然后我们看看注册两个控件的右键处理事件如下：

       /// <summary>
        /// Invoked when this page is about to be displayed in a Frame.
        /// </summary>
        /// <param name="e">Event data that describes how this page was reached.  The Parameter
        /// property is typically used to configure the page.</param>
        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            base.OnNavigatedTo(e);
            //上下文菜单
            this.tbName.ContextMenuOpening += tbName_ContextMenuOpening;
            //右键菜单
            this.gdMenu.RightTapped += gdMenu_RightTapped;
        }

        /// <summary>
        /// 右键菜单事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void gdMenu_RightTapped(object sender, RightTappedRoutedEventArgs e)
        {
            SetRightClick(sender);
        }

        /// <summary>
        /// 上下文菜单
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void tbName_ContextMenuOpening(object sender, ContextMenuEventArgs e)
        {
            SetRightClick(sender);
        }

        /// <summary>
        /// 事件卸载
        /// </summary>
        /// <param name="e"></param>
        protected override void OnNavigatedFrom(NavigationEventArgs e)
        {
            base.OnNavigatedFrom(e);
            //上下文菜单
            this.tbName.ContextMenuOpening -= tbName_ContextMenuOpening;
            //右键菜单
            this.gdMenu.RightTapped -= gdMenu_RightTapped;
        }

　　再次看看前台Xaml代码如下：

    <Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}" Name="gdMenu">
        <TextBox HorizontalAlignment="Left" Margin="141,164,0,0" TextWrapping="Wrap"
                 Name="tbName" Text="" VerticalAlignment="Top" Height="157" Width="540"/>
        <TextBox HorizontalAlignment="Left" Margin="210,353,0,0" TextWrapping="Wrap" 
                 Name="tbText" Text="" VerticalAlignment="Top" Width="290"/>
    </Grid>

　　如需源码请点击 Win8Menu.rar 下载,下面是效果图.