Partial Type in C#

Partial type is a new feature introduced in .Net 2.0 (VS2005). Using Partial type you can define a single class in multiple files (more than one files) at compilation time these classes are combined into a single class. You can apply partial modifier on a class or a struct, or an interface.

Partial modifier is not available on delegate or enumeration declarations.

There are a few things that you should be careful about when writing code for partial classes:

·         All the partial types must be defined within a same assembly and module.

·         Method signatures (return type, name of the method, and parameters) must be unique for the aggregated typed (which was defined partially).

·         The partial types must have the same accessibility.

·         Inheritance at any partial type applies to the entire class.

·         If any part is sealed, the entire class is sealed.

·         If any part is abstract, the entire class is abstract.

Example

//partial class

public partial class Employee

{

public virtual void GetEmployeeNo();

}

public partial class Employee

{

public virtual void GetEmployeeName();

}

//Derived class

public class Department : Employee

{

       public void getEmployeeDetails()

       {

     GetEmployeeNo ();

     GetEmployeeName ();

       }

}