Null keyword C#

C# > Keywords > Null

Null represent reference that does not refer to any object.

• default value of reference type variables
• ordinary value types cannot be null

Example

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace WindowsFormsApplication2

{

    public class TestClass

    {

        public void TestMethod() { }

    }

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

           

            TestClass tc=null;

            tc = new TestClass();

            tc.TestMethod();   // You can call TestMethod method.

            tc = null; // set tc to null => the object is no longer accessible and can now be garbage collected

           

            string s1 = null;

            //int k = null; // Error Cannot convert null to 'int' because it is a non-nullable value type  

            int? k = null; // use a nullable value type instead OK

        }

    }

}