c# 不通过注册表，检测系统安装的.net版本

        /// <summary>
        /// 检测是否安裝4.7.2以上版本
        /// </summary>
        /// <returns></returns>
        bool CheckNet472()
        {
            //C:\Windows\Microsoft.NET\Framework
            string net = "Microsoft.NET";
            string mscorlibFile = "mscorlib.dll";
            string RuntimeDirectory = System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory();
            int index = RuntimeDirectory.IndexOf(net);
            if (index == -1)
            {
                MessageBox.Show(RuntimeDirectory, "錯誤，找不到系统路径");
                return false;
            }
            string NetDirectory = RuntimeDirectory.Substring(0, index + net.Length);
            string Framework = Path.Combine(Path.Combine(NetDirectory, Path.Combine("Framework", "v4.0.30319")), mscorlibFile);
            string Framework64 = Path.Combine(Path.Combine(NetDirectory, Path.Combine("Framework64", "v4.0.30319")), mscorlibFile);
            int Nub = 0;
            if (File.Exists(Framework))
            {

                Nub = GetFileVersion(Framework);
            }
            else if (File.Exists(Framework64))
            {
                Nub = GetFileVersion(Framework64);
            }


            if (Nub > 471)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        int GetFileVersion(string FilePath)
        {
            FileVersionInfo fileVersionInfo = FileVersionInfo.GetVersionInfo(FilePath);
            string Version = fileVersionInfo.ProductVersion;
            string res = new string(Version.Where(char.IsDigit).ToArray());
            if (res.Length > 1)
            {

                int NubCode = Convert.ToInt32(res.Substring(0, 3));
                return NubCode;
            }
            return 0;
        }