替换Webbrowser默认的弹出菜单

using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Windows.Forms;
 using System.Threading;
 using HtmlDom;
 namespace HTMLElementSelect
 {
     public partial class Form1 : Form
     {
         public Form1()
         {
             InitializeComponent();
         }
         AboutForm afrm=new AboutForm();
         private void Form1_Load(object sender, EventArgs e)
         {
             webBrowser1.Navigate("http://www.cnblogs.com/JiangHuakey/"); 
            webBrowser1.ContextMenuStrip = contextMenuStrip1;    //! 设置我们自己的弹出菜单
             webBrowser1.IsWebBrowserContextMenuEnabled = false;  //! 禁用IE默认的弹出菜单
         }
 
        private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
         {
             //! 屏幕坐标
             Point ScreenCoord = new Point(MousePosition.X, MousePosition.Y);
             //! 浏览器坐标
             Point BrowserCoord = webBrowser1.PointToClient(ScreenCoord);
             HtmlElement elem = webBrowser1.Document.GetElementFromPoint(BrowserCoord);
 
            //! 隐藏所有菜单项
             for (int i = 0; i < contextMenuStrip1.Items.Count; i++)
             {
                 contextMenuStrip1.Items[i].Visible = false;
             }
 
            //! 显示对应的菜单
             switch (elem.TagName)
             {
                 case "A":
                     //! 如果是一个超链接，则显示相关超链接的菜单项
                     openToolStripMenuItem.Visible = true;
                     openInNewTabToolStripMenuItem.Visible = true;
                     openInNewWindowToolStripMenuItem.Visible = true;
                     break;
                 case "IMG":
                     //! 如果是图片，则显示相关图片的菜单项
                     saveImageToolStripMenuItem.Visible = true;
                     setAsDesktopWallpaperToolStripMenuItem.Visible = true;
                     break;
                 default:
                     //! 其它
                     refreshToolStripMenuItem.Visible = true;
                     viewSourceToolStripMenuItem.Visible = true;
                     break;
             }
         }
         
        void SaveImageToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
         
        void SetAsDesktopWallpaperToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
         
        void OpenToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
         
        void OpenInNewTabToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
         
        void OpenInNewWindowToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
         
        void RefreshToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
         
        void ViewSourceToolStripMenuItemClick(object sender, EventArgs e)
         {
          afrm.Show();
         }
     }
 }