What is a static constructor in C#?

A static constructor is a constructor declared using a static modifier. It is the first block of code executed in a class. With that, a static constructor executes only once in the life cycle of class.

The following is an example of static constructors in C# −

Example

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Difference {
   class Demo {
      static int val1;
      int val2;

      static Demo() {
         Console.WriteLine("This is Static Constructor");
         val1 = 70;
      }

      public Demo(int val3) {
         Console.WriteLine("This is Instance Constructor");
         val2 = val3;
      }
   
      private void show() {
         Console.WriteLine("First Value = " + val1);
         Console.WriteLine("Second Value = " + val2);
      }

      static void Main(string[] args) {
         Demo d1 = new Demo(110);
         Demo d2 = new Demo(200);
         d1.show();
         d2.show();
         Console.ReadKey();
      }
   }
}