Working with static in C#

A method that does not have anything to do with the object's state can be marked as a static method. Static methods and properties can only access static fields and static events.

Here is an example:

class File {  
    public string srcPath;  
    public void Copy(string destPath) {...  
    }  
    public static void Copy(string srcPath, string destPath) {...  
    }  
}   

Note

All methods and properties (procedures) of the class, irrespective of whether they are static, are allocated memory for instructions only once.

1. Outside the class, static members of a class can be accessed using class names, whereas the instance member of a class must be accessed using a reference variable referring to an object of that class.
2. Instance members of the class cannot be accessed in a static constructor or any other static method or property of the class (unless it is qualified by a reference variable referring to an object of that class).

For example,

public static void Foo() {  
    //this._Balance = 100; // Is Invalid  
    Accout a = new Account();  
    a._Balance = 100; // IsValid because _Balance is qualified by “a” which is reference to an object.  
} 

1. An instance member can access static members of the class.
2. “this” cannot be used in the static member of a class.

Static Class

A class in C# can be declared as static; such a class can have only static members, and instance members are not allowed. Also, such a class cannot be instantiated.

It is ideally used for managing Global data.

static class Demo {  
    public static int P1;  
    public static void Foo() {}  
}  

Example

If a static class contains non-static members, it gives an error.

Example program using a static keyword

A complete C# program uses a static class with static fields, static properties, a static constructor, and a static method.

using System;  
namespace Article__Static {  
    static class Program {  
        static string name;  
        private static string _subject;  
        public static string subject {  
            get {  
                return _subject;  
            }  
            set {  
                _subject = value;  
            }  
        }  
        static Program() {  
            Console.WriteLine("static constructor.");  
            name = "static member.”  
        }  
        public static void Display() {  
            Console.WriteLine("static method.” + name);   
            }  
            static void Main(string[] args) {  
                Program.subject = "CSharp";  
                Console.WriteLine(Program.subject);  
                Program.Display();  
            }  
        }  
    }  

Output

Summary

This article taught us all about the static keyword in C#. The C# static keyword is used to declare static classes, static members, static methods, and static properties.