how to add a property to a component that will reflect on the object inspector

Question

in Delphi 7 , when adding a propery to an object, how is it possible to see that property in the object inspector?

Answer 1

Make the property published. For instance,

private
  FMyProperty: integer;
published
  property MyProperty: integer read FMyProperty write FMyProperty;

Often, you need to repaint the control (or do some other processing) when a property is changed. Then you can do

private
  FMyProperty: integer;
  procedure SetMyProperty(MyProperty: integer);
published
  property MyProperty: integer read FMyProperty write SetMyProperty;

...

procedure TMyControl.SetMyProperty(MyProperty: integer);
begin
  if FMyProperty <> MyProperty then
  begin
    FMyProperty := MyProperty;
    Invalidate; // for example
  end;
end;

Answer 2

Add that property to the published section, it will make it appear on the Object Inspector, like this:

TMyComponent = class(TComponent)
 ...
published
  property MyProperty: string read FMyProperty write SetMyProperty;