asked on

How to sublass...

I am reasonly new at the object side of Delphi. Using D3. I have purchased a 3rd party toolset with source, InfoPower. They have a class, TwwDBEdit that I wish to make a similar class, but with an underline for a field instead of a complete border. When I asked InfoPower about this, they said "I suppose you could subclass the component, and set the borderstyle to none, and have the wmpaint method paint the line the way you want..".

This is all fine and well, if I knew what I was doing... <g>. Can someone give me a shove in the right direction.
-- Code fragments greatly appreciated --

Also, how do I get my new control to show up on the VCL controls panel.

Thanks

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viktornet

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gspears060598

ASKER

hi,

Your answer is just about complete. Can you give me a little help with the wm_paint. I was told this is what I need to use to draw the line. I'd like it to be 3D, but I'll take what I can get. I've tried to look up information, but haven't had a whole lot of luck yet...

viktornet

Here is a code I've tried with the TLabel component.....It is not finished yet, but it will show you how to draw a 3D underlining under the caption of the label....
----------------
unit Label1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;

type
TLabel1 = class(TLabel)
private
{ Private declarations }
protected
{ Protected declarations }
public
procedure Paint;override;
Constructor Create(AOwner : TComponent);override;
published
{ Published declarations }
end;

procedure Register;

implementation
Constructor TLabel1.Create(AOwner : TComponent);
begin
Inherited Create(AOwner);
end;

procedure TLabel1.Paint;
var
High : Integer;
begin
Inherited Paint;
High := Canvas.TextHeight(Caption) + 1;
Canvas.Pen.Color := clBtnShadow;
Canvas.MoveTo(0, High - 1);
Canvas.LineTo(Canvas.TextWidth(Caption),High - 1);

Canvas.Pen.Color := clBtnHighLight;
Canvas.MoveTo(0, High + 1);
Canvas.LineTo(Canvas.TextWidth(Caption),High + 1);

Canvas.Pen.Color := Font.Color;
Canvas.MoveTo(0, High);
Canvas.LineTo(Canvas.TextWidth(Caption),High);
end;

procedure Register;
begin
RegisterComponents('Samples', [TLabel1]);
end;

end.
-------------
Hope this helps =)

Regards,
Viktor Ivanov