Add a border icon to the form

Using Delphi I would like to add another button to the border icon buttons; close, maximize, minimize. Any ideas on h开发者_开发问答ow to do this?

This was easy to do prior to Windows Aero. You simply had to listen to the WM_NCPAINT and WM_NCACTIVATE messages to draw on top of the caption bar, and similarly you could use the other WM_NC* messages to respond to mouse clicks etc, in particular WM_NCHITTEST, WM_NCLBUTTONDOWN, and WM_NCLBUTTONUP.

For instance, to draw a string on the title bar, you only had to do

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
  protected
    procedure WMNCPaint(var Msg: TWMNCPaint); message WM_NCPAINT;
    procedure WMNCActivate(var Msg: TWMNCActivate); message WM_NCACTIVATE;
  private
    procedure DrawOnCaption;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ TForm1 }

procedure TForm1.WMNCActivate(var Msg: TWMNCActivate);
begin
  inherited;
  DrawOnCaption;
end;

procedure TForm1.WMNCPaint(var Msg: TWMNCPaint);
begin
  inherited;
  DrawOnCaption;
end;

procedure TForm1.DrawOnCaption;
var
  dc: HDC;
begin
  dc := GetWindowDC(Handle);
  try
    TextOut(dc, 20, 2, 'test', 4);
  finally
    ReleaseDC(Handle, dc);
  end;
end;

end.

Now, this doesn't work with Aero enabled. Still, there is a way to draw on the caption bar; I have done that, but it is far more complicated. See this article for a working example.

Chris Rolliston wrote a detailed blog about creating a custom title bar on Vista and Windows 7.

He also wrote a follow up article and posted example code on CodeCentral.

Yes, set the form's border style property to bsNone and implement your own title bar with all the buttons and custom behaviour you like.