Getting started with classes (1): Inheriting forms

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; procedure button1click (Sender: tobject); Procedure button2click (Sender: tobject); Private {private Declarations} public {public declarations} end; {inherit the tform1 class: tmyform} tmyform = Class (tform1) Procedure button1click (Sender: tobject); end; var form1: tform1; // declare the tform1 instance myform1: tmyform; // declare the tmyform instance implementation {$ R *. DFM} // There are two buttons on form1, button1: pop-up information; button2: Create and display myform1procedure tform1.button1click (Sender: tobject); begin showmessage ('tform1 '); end; procedure tform1.button2click (Sender: tobject); begin myform1: = tmyform. create (NiL); myform1.show; end; {tmyform} // After tmyform1 is created, it should be the same as tform1; // button2: create a new tmyform1 // button1: two messages are displayed, because a procedure tmyform is inherited. button1click (Sender: tobject); begin inherited; // inherits the original function showmessage ('tmyform'); end.