Partial Methods In C#

We already have the concept of Partial Classes in C# but I never knew that we can also have Partial Methods. Yes, we can have Partial Methods in C#. This concept also uses the Partial keyword but there are some restrictions/guidelines with the use of the Partial Methods. These are given below.

1. A Partial Method can only be created in other Partial Classes or Partial Structs.
2. In order to create a Partial method, it must be declared first(like an abstract method), with a signature only and no definition. After it is declared, its body can be defined in the same component or different component of the Partial Class/Struct .
3. A Partial Method is implicitly private. It cannot have any other access modifier.
4. A Partial Method can only have void return type.

Let's see how we can create a Partial Method. We start by creating a Partial Class ClassA and add a Partial Method declaration.

public partial class ClassA
   {
       partial void GetData();
   }

Now, create the second component of the Partial Class ClassA and add the implementation of the Partial Method. 

public partial class ClassA
  {
      partial void SetData()
      {
          // Perform functionality here
      }
  }

In order to test the Partial Method, we add another method and call this private method inside this newly created method.

class Program
   {
       static void Main(string[] args)
       {
           ClassA cls = new ClassA();
           cls.SetSalary();
       }
   }
   public partial class ClassA
   {
       partial void SetData();
   }

   public partial class ClassA
   {
       public void SetSalary()
       {
           SetData();
           // Perform other functionality here
       }
       partial void SetData()
       {
           Console.Write("This is partial method.");
           Console.ReadKey();
       }
   }

Run the code and see the result. I hope you enjoyed reading it. Happy coding.