Partial Class and Method

Declaring a class as “partial” enables the developer to extend the capabilities of class to add extra members with in by creating the same partial class in an another file.

Ex:-

I can create below class in “Class1.cs”

  public partial class Class1

    {

        public void Method1()

        {

            Console.WriteLine("Hello this is method1");

        }

    }

I can also create a class with same name (Class1) as below, in “Class2.cs”, which means I am trying to add functions to an existing partial class.

  public partial class Class1

    {

        public void Method2()

        {

            Console.WriteLine("Hello this is method2");

        }

    }

Similarly, partial methods can be declared in a partial class and can be implemented in the specific partial class. Below example demonstrates the same.

Program.cs

    public partial class MyClass1

    {

        public void Met1()

        {

            Console.WriteLine("Method 1");

            Met2();

        }

         partial void Met2();

    }

MyClass.cs

  public partial class MyClass1

    {

        partial void Met2()

        {

            Console.WriteLine("Method 2");

        }

    }

Now when I create instance for “MyClass1” and invoke “Met1”, “Met1” when calls “Met2” it calls the implemented function in specific partial class.

Note: Partial methods cannot be declared with access specifiers and also cannot be invoked from the object of the class directly which in turn can be called in an another function(s).