Static Class :
A static class is you can say same as the non-static class, but there is one difference them is a static class can't be instantiated. In other words, you cannot use the "new" keyword to create a instance variable of the class type. As there is no instance variable, you can access the members of a static class by using the name of the class itself. Static classes and it's class members are used to create data and functions that can be accessed without creating an instance of the class. Static class members can be used to separate data and behavior that is independent of any object identity: the data and functions do not change regardless of what happens to the object. Static classes can be used when data or behavior is not present in the class that depends on object identity. Static classes are loaded automatically by the .NET Framework CLR when that program or namespace containing the class is loaded.
The main features of a static class are:
static classes can only contain static members.
static classes can not be instantiated.
static classes are sealed and therefore cannot be inherited.