What is a "static" class?

Question

In C# what is the difference between:

public static class ClassName {}

And:

public class ClassName {}

Answer 1

A static class cannot be instantiated, and can contain only static members. Hence, the calls for a static class are as: MyStaticClass.MyMethod(...) or MyStaticClass.MyConstant.

A non static class can be instantiated and may contain non-static members (instance constructors, destructor, indexers). A non-static member of a non-static class is callable only through an object:

MyNonStaticClass x = new MyNonStaticClass(...);
x.MyNonStaticMethod(...);