检测NET框是否安装

     public static bool CheckIfDotNetFrameworkInstalled(string version)
        {
            return CheckIfDotNetFrameworkInstalled(version, 0);
        }

        public static bool CheckIfDotNetFrameworkInstalled(string version, int servicePack)
        {
            bool isInstalled = false;

            RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(string.Format("SOFTWARE//Microsoft//NET Framework Setup//NDP//v{0}", version));
            if (registryKey != null)
            {
                if (Convert.ToInt32(registryKey.GetValue("Install", 0)) == 1)
                {
                    if (servicePack > 0)
                    {
                        if (Convert.ToInt32(registryKey.GetValue("SP", 0)) == servicePack)
                        {
                            isInstalled = true;
                        }
                    }
                    else
                    {
                        isInstalled = true;
                    }
                }
            }

            return isInstalled;
        }