How to Get Dotnet Version Using Powershell

using System;
using Microsoft.Win32;

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 != null && 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 >= enables forward compatibility.
      string CheckFor45PlusVersion(int releaseKey)
      {
         if (releaseKey >= 528040)
            return "4.8 or later";
         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";      
         // 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

$subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\"

Get-ChildItem 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP' -recurse |
Get-ItemProperty -name Version,Release -EA 0 |
Where { $_.PSChildName -match '^(?![SW])\p{L}'} |
Select PSChildName, Version, Release, @{
  name="Product"
  expression={
      switch -regex ($_.Release) {
        "378389" { [Version]"4.5" }
        "378675|378758" { [Version]"4.5.1" }
        "379893" { [Version]"4.5.2" }
        "393295|393297" { [Version]"4.6" }
        "394254|394271" { [Version]"4.6.1" }
        "394802|394806" { [Version]"4.6.2" }
        "460798|460805" { [Version]"4.7" }
        "461308|461310" { [Version]"4.7.1" }
        "461808|461814" { [Version]"4.7.2" }
        "528040|528049" { [Version]"4.8" }
        {$_ -gt 528049} { [Version]"New Version (> 4.8), please include version in the script" }
      }
    }
}