string strProject = "Exec";
string p_FileTypeName =".cdb";//文件后綴
            string fileName = System.Windows.Forms.Application.ExecutablePath;// 獲取啟動了應用程序的可執行文件的路徑及文件名
            //string startPath = System.Windows.Forms.Application.StartupPath;//獲取啟動了應用程序的可執行文件的路徑
       //注冊文件類型            
       Registry.ClassesRoot.CreateSubKey(p_FileTypeName).SetValue("", strProject, RegistryValueKind.String);
            using (RegistryKey key = Registry.ClassesRoot.CreateSubKey(strProject))
            {
                //設置圖標
                RegistryKey iconKey = key.CreateSubKey("DefaultIcon");
                iconKey.SetValue("", System.Windows.Forms.Application.StartupPath + "\\ooopic_1564036072.ico");
                //設置默認啟動程序
                key.CreateSubKey(@"Shell\Open\Command").SetValue("", fileName + " \"%1\"", RegistryValueKind.ExpandString);
            }