取扩展名对于的应用程序列表

我想实现右键-》打开方式-》可用应用程序列表。有成型的代码吗谢谢了 --------------------编程问答--------------------

--------------------编程问答-------------------- public enum ShowCommands : int
        {
            SW_HIDE = 0,
            SW_SHOWNORMAL = 1,
            SW_NORMAL = 1,
            SW_SHOWMINIMIZED = 2,
            SW_SHOWMAXIMIZED = 3,
            SW_MAXIMIZE = 3,
            SW_SHOWNOACTIVATE = 4,
            SW_SHOW = 5,
            SW_MINIMIZE = 6,
            SW_SHOWMINNOACTIVE = 7,
            SW_SHOWNA = 8,
            SW_RESTORE = 9,
            SW_SHOWDEFAULT = 10,
            SW_FORCEMINIMIZE = 11,
            SW_MAX = 11
        }

        [DllImport("shell32.dll ")]
        static extern IntPtr ShellExecute(
                IntPtr hwnd,
                string lpOperation,
                string lpFile,
                string lpParameters,
                string lpDirectory,
                ShowCommands nShowCmd);

        private void OpenStyle_Click(object sender, EventArgs e)
        {
            ShellExecute(IntPtr.Zero, "open", "rundll32.exe", " shell32.dll OpenAs_RunDLL *.ext", null, ShowCommands.SW_NORMAL);
        }

        private void Form3_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right)
            {
                OpenStyle = new ToolStripMenuItem();
                this.ContextMenuStrip = contextMenuStrip1;
            }
        } --------------------编程问答--------------------



   public enum ShowCommands : int

   {

            SW_HIDE = 0,

            SW_SHOWNORMAL = 1,

            SW_NORMAL = 1,

            SW_SHOWMINIMIZED = 2,

            SW_SHOWMAXIMIZED = 3,

            SW_MAXIMIZE = 3,

            SW_SHOWNOACTIVATE = 4,

            SW_SHOW = 5,

            SW_MINIMIZE = 6,

            SW_SHOWMINNOACTIVE = 7,

            SW_SHOWNA = 8,

            SW_RESTORE = 9,

            SW_SHOWDEFAULT = 10,

            SW_FORCEMINIMIZE = 11,

            SW_MAX = 11

    }



    [DllImport("shell32.dll ")]

     static extern IntPtr ShellExecute(

        IntPtr hwnd,

        string lpOperation,

        string lpFile,

        string lpParameters,

        string lpDirectory,

        ShowCommands nShowCmd); 



    private void OpenStyle_Click(object sender, EventArgs e)

    {

         ShellExecute(IntPtr.Zero, "open", "rundll32.exe", " shell32.dll OpenAs_RunDLL *.ext", null, ShowCommands.SW_NORMAL);   

    }



    private void Form3_MouseUp(object sender, MouseEventArgs e)

    {

         if (e.Button == MouseButtons.Right)

         {

                this.ContextMenuStrip = contextMenuStrip1;

         }

     }

contextMenuStrip1是一个包含了OpenStyle(打开方式)的ContextMenuStrip

补充：.NET技术 ,  C#