What are partial classes?

A partial class is only used to split the definition of a class in two or more classes in the same source code file or more than one source file. You can create a class definition in multiple files, but it will be compiled as one class at run time. Also, when you create an instance of this class, you can access all the methods from all source files with the same object.

Partial Classes can be created in the same namespace. It isn’t possible to create a partial class in a different namespace. So use the “partial” keyword with all the class names that you want to bind together with the same name of a class in the same namespace.

 

public partial Clas_name  
{
        // code
}

Let’s see an example:

// C# program to illustrate the problems 
// with public and private members 
using System;
public partial class Coords
{
    private int x;
    private int y;
    public Coords(int x, int y)
    {
        this.x = x;
        this.y = y;
    }
}
public partial class Coords
{
    public void PrintCoords()
    {
        Console.WriteLine("Coords: {0},{1}", x, y);
    }
}
class TestCoords
{
    static void Main()
    {
        Coords myCoords = new Coords(6, 27);
        myCoords.PrintCoords();
        // Keep the console window open in debug mode.
        Console.WriteLine("Press any key to exit.");
        Console.ReadKey();
    }
}

Output: