When developing an application using C# , one would have noticed the usage of String and string class .

In the below example we use 2 string variable

string str1 = "Ginktage.com World";

String str2 = "Ginktage.com World"; 

What is the difference between String and string in C# ?

System.String is a .NET Framework type whereas string is simply an alias for the System.String class . They both compile to the similar code in IL (Intermediate Code), so at execution time there is no difference.

string cannot be used as a variable name since it is a reserved word unless we use it with the @ symbol. If one needs to declare a variable called String , there are possibilities to do it as shown below.

using System;

namespace GinktageConsoleApp
{
    internal class Program
    {
        private static Random randomNumber = new Random();

        private static void Main(string[] args)
        {
            string String = "This is a String variable";
            string string = "Invalid Variable Name";
            Console.ReadLine();
        }
    }
}