C#编程：创建文件关联与自定义图标教程

 private void button1_Click(object sender, EventArgs e)
        {
            string fileType = textBox1.Text;
            if (!fileType.StartsWith("."))
            {
                fileType = "." + fileType;
                textBox1.Text = fileType;
            }
             //Application.StartupPath 这个只是路径
             // Environment.CommandLine ; 这个包含参数
            string appName = Application.ExecutablePath;
          
            RegistryKey hk_root = Registry.ClassesRoot; //HKEY_CLASSES_ROOT
           

            //注册自己程序的the ProgID
            if (null == hk_root.OpenSubKey("widebright.mp3")) //The proper format of a ProgID key name is [Vendor or Application].[Component].[Version], separated by periods and with no spaces, as in Word.Document.6. The Version portion is optional but strongly recommended (see Using Versioned PROGIDs).
            {
                RegistryKey progID = hk_root.CreateSubKey("widebright.mp3");
                if (progID == null) 
                {
                    MessageBox.Show("创建widebright.mp3 类型ProgID时失败");
                    hk_root.Close();
                    return;
                }
                //创建（默认）键值，显示给用户看的文件类型描述
                progID.SetValue("", "widebright专用的mp3文件 ", RegistryValueKind.String );

                //文件显示的图标
                RegistryKey defaultIcon = progID.CreateSubKey("DefaultIcon");