A utility to check the .NET Framework version instead of manually checking the registry and comparing the key value (use .NET 4 target framework)

Program.cs

// Note: this is a slightly modified version of an example from - https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/how-to-determine-which-versions-are-installed
using System;
using Microsoft.Win32;

namespace GetDotNetVersion
{
    public class GetDotNetVersion
    {
        public static void Main()
        {
            Get45PlusFromRegistry();
        }

        private static void Get45PlusFromRegistry()
        {
            const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";

            using (var ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey))
            {
                if (ndpKey?.GetValue("Release") != null)
                {
                    Console.WriteLine(".NET Framework Version: " + CheckFor45PlusVersion((int)ndpKey.GetValue("Release")));
                }
                else
                {
                    Console.WriteLine(".NET Framework Version 4.5 or later is not detected.");
                }
            }
        }

        // Checking the version using >= will enable forward compatibility.
        private static string CheckFor45PlusVersion(int releaseKey)
        {
            if (releaseKey >= 460798)
            {
                return "4.7 or later";
            }

            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";
            }

            // This code should never execute. A non-null release key should mean
            // that 4.5 or later is installed.
            return "No 4.5 or later version detected";
        }
    }
}
// This example displays output like the following:
//       .NET Framework Version: 4.6.1