You don't have to use inheritance in the above scenario, inheritance is used to kind of have a starting point.
For example if you inherit a class from a TextBox object, your class is exactly the same as the TextBox class
public class MyCustomTextbox : System.Windows.Forms.Textbox
{
}
You can use inheritance to add or manipulate functionality to an existing type. In this example you can add or modify functionality to the TextBox control, for example Validation or something.
Have fun,
Eduard