Partial Class in C# with example, What is the use of partial class (Oops Programming)

Now in this tutorial we will see what is partial class in C#, why use of partial class,difference between partial class and class in C#.

Description:

What is partial Class in C#? Difference between partial class and class?

In Object Oriented Programming it is possible to split the definition of a class or a struct, or an interface over two or more source files.Each source file contains a section of the class definition, and all parts are combined when the application is compiled. So a partial class is one which looks like a class except it is defined in multiple files. To Split a class definition , use partial keyword modifier.

Why we use partial classes:

• This feature allows us to write single class file into multiple files so that multiple programmers can work at a time.
• When working with automatically generated source, code can be added to class without having to recreate the source file.

Partial Class in C# with example:

 Take a class and name it as part1.cs in your console application project and write below.

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1.     namespace OOPSProject  

2.     {  

3.         partial class Parts  

4.         {  

5.             public void Method1()  

6.             {  

7.                 Console.WriteLine("Method 1");   

8.             }  

9.             public void Method2()  

10.         {  

11.             Console.WriteLine("Method 2");  

12.         }  

13.     }  

14. }  

Take another class and name it part2.cs and write below code.

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1. namespace OOPSProject  
2. {  
3.     partial class Parts  
4.     {  
5.         public void Method3()  
6.         {  
7.             Console.WriteLine("Method 3");  
8.         }  
9.         public void Method4()  
10.         {  
11.             Console.WriteLine("Method 4");  
12.         }  
13.     }  
14. }  

To test these two classes take another class and name it as testpart.cs and write below code .

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1. namespace OOPSProject  
2. {  
3.     class TestParts  
4.     {  
5.         static void Main()  
6.         {  
7.             Parts p = new Parts();  
8.             p.Method1(); p.Method2();  
9.             p.Method3(); p.Method4();    
10.             Console.ReadLine();   
11.         }  
12.     }  
13. }  

Key Points while writing Partial Classes in C#:

• All the parts of the class must be defined within the namespace( same assembly or same module).
• All the parts must be used with partial keyword.
• All the parts must be available at compile time to form the final class.
• All the parts must have the same accessibility level, such as public, private,protected
  and so on.
• if any part of the class is declared as abstract then whole type is considered as abstract in the same
  manner for the sealed.
• If any part is declares a base type, then the whole type inherits that class.
• partial modifier is not available on delegate or enumeration declarations.
   

Conclusion:

I hope you got an idea on how to and when to use partial classes with example and what precaution we should take care while writing partial classes. I would love to take feedback from my readers about my this writing.

- See more at: http://aspdotnet-sekhar.blogspot.in/2013/07/parital-class-in-csharp-example-what-is-the-use-difference-to-class.html#sthash.aKmkKQUv.dpuf