Rehber C# ile sistemde yüklü olan .NET Framework sürümünü öğrenme

using System;
using Microsoft.Win32;

const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";
             using (var ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey)){
                 if (ndpKey != null && ndpKey.GetValue("Release") != null){
                     Console.WriteLine($".NET Framework Sürümü: {CheckFor45PlusVersion((int)ndpKey.GetValue("Release"))}");
                 }else{
                     Console.WriteLine("NET Framework Sürüm 4.5 veya üstü algılanmadı.");
                 }
             }
             string CheckFor45PlusVersion(int releaseKey){
                 if(releaseKey >= 533320)
                     return "4.8.1 veya daha üstü bir sürüm mecvut.";
                 if (releaseKey >= 528040)
                     return "4.8";
                 if (releaseKey >= 461808)
                     return "4.7.2";
                 if (releaseKey >= 461308)
                     return "4.7.1";
                 if (releaseKey >= 460798)
                     return "4.7";
                 if (releaseKey >= 394802)
                     return "4.6.2";
                 if (releaseKey >= 394254)
                     return "4.6.1";
                 if (releaseKey >= 393295)
                     return "4.6";
                 if (releaseKey >= 379893)
                     return "4.5.2";
                 if (releaseKey >= 378675)
                     return "4.5.1";
                 if (releaseKey >= 378389)
                     return "4.5";
                 return "4.5 veya daha sonraki sürümler tespit edilmedi.";
             }

// Open the registry key for the .NET Framework entry.
            using (RegistryKey ndpKey =
                    RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).
                    OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
            {
                foreach (var versionKeyName in ndpKey.GetSubKeyNames())
                {
                    // Skip .NET Framework 4.5 version information.
                    if (versionKeyName == "v4")
                    {
                        continue;
                    }

                    if (versionKeyName.StartsWith("v"))
                    {
                        RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);

                        // Get the .NET Framework version value.
                        var name = (string)versionKey.GetValue("Version", "");
                        // Get the service pack (SP) number.
                        var sp = versionKey.GetValue("SP", "").ToString();

                        // Get the installation flag.
                        var install = versionKey.GetValue("Install", "").ToString();
                        if (string.IsNullOrEmpty(install))
                        {
                            // No install info; it must be in a child subkey.
                            Console.WriteLine($"{versionKeyName}  {name}");
                        }
                        else if (install == "1")
                        {
                            // Install = 1 means the version is installed.

                            if (!string.IsNullOrEmpty(sp))
                            {
                                Console.WriteLine($"{versionKeyName}  {name}  SP{sp}");
                            }
                            else
                            {
                                Console.WriteLine($"{versionKeyName}  {name}");
                            }
                        }

                        if (!string.IsNullOrEmpty(name))
                        {
                            continue;
                        }
                        // else print out info from subkeys...

                        // Iterate through the subkeys of the version subkey.
                        foreach (var subKeyName in versionKey.GetSubKeyNames())
                        {
                            RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                            name = (string)subKey.GetValue("Version", "");
                            if (!string.IsNullOrEmpty(name))
                                sp = subKey.GetValue("SP", "").ToString();

                            install = subKey.GetValue("Install", "").ToString();
                            if (string.IsNullOrEmpty(install))
                            {
                                // No install info; it must be later.
                                Console.WriteLine($"{versionKeyName}  {name}");
                            }
                            else if (install == "1")
                            {
                                if (!string.IsNullOrEmpty(sp))
                                {
                                    Console.WriteLine($"{subKeyName}  {name}  SP{sp}");
                                }
                                else
                                {
                                    Console.WriteLine($"  {subKeyName}  {name}");
                                }
                            }
                        }
                    }
                }
            }

Console.WriteLine(Environment.Version);