inheritace in C# windows applicatin

Windows Forms are for User Interface.
inheritance, Method Overriding are concepts.This is not matter you used in Windows or console application.They have same approch
If you see inheritence in windows application,

public partial class Form1 : Form

The Form1 inherits Form class.
See this example
Override
now instead of writting this

Console.WriteLine("Area of the square = {0}", sq.Area());

take value and assign to a textbox in Windows Form.
That will be Overriing with windows application