Decode URL

 

.NET Core

If you are using .NET Core (either ASP .NET, a Class library or a Console App) or even .NET Standard, you can use one of these two methods:-

System.Web.HttpUtility.UrlDecode

OR

System.Net.WebUtility.UrlDecode

ASP .NET Framework

If you are inside an instance method of System.Web.Mvc.Controller, you can use the Server property as follows:-
Server.UrlDecode

For any other class, you can use one of these:-
System.Web.HttpUtility.UrlDecode

OR

System.Net.WebUtility.UrlDecode

.NET Framework Console/Desktop Application

For the remaining portions of the .NET platform like a .NET Framework Console Application, Class Library, Windows Service & Desktop Application you can use the following:-
System.Net.WebUtility.UrlDecode

On a side note, you can try my online URL Decoder.