Static Members

Instance vs Static

Instance members belong to a specific object; every object gets its own copy. Static members belong to the class itself, shared across every instance.

Static Fields

class Counter
{
    public static int Count = 0;

    public Counter()
    {
        Count++; // shared across every instance
    }
}

new Counter();
new Counter();
new Counter();
Console.WriteLine(Counter.Count);

Static Methods

Static methods belong to the class, not an object, and can only directly access other static members. Math.Sqrt() and Console.WriteLine() are both static methods.

class MathHelper
{
    public static int Square(int n) => n * n;
}

Console.WriteLine(MathHelper.Square(5)); // no object needed

Static Classes

A class marked static can contain only static members and can never be instantiated — used for pure utility classes.

static class Constants
{
    public const double TaxRate = 0.08;
}

Console.WriteLine(Constants.TaxRate);

FAQs

Summary