How-to-add-Taskbar-Buttons-for-SubForms-and-manage-them-correctly


            Title: How to add Taskbar-Button's for SubForms and manage them correctly.
Question: I would like to add some Windows' Taskbar-Buttons for dynamic created forms w/o loosing the ability to 're-focus' the MainForm by clicking it's own button.
Answer:
The following example uses a Button (Button1)to
dynamic create forms at runtime. Each form will be
accessable via a corresponding Button placed on the 
Taskbar. You had to include the WMSysCommand method
to enable the real "look&feel" of minimizing the MainForm.
Otherwise, the MainForm will be minimized to the lower left
side of the Screen or will be hidden in the background, so
it's not possible to restore it correctly.
If you want to minimize (or hide) all subforms when
minimizing the MainForm, you had to iterate through all
registered subforms and hide them manualy. I don't know a
better way right now, but if you've found any solution...:-)
MainForm Unit
unit MainForm;
interface
uses
 Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
 StdCtrls;
type
 TMainForm = class(TForm)
 Button1: TButton;
 procedure FormCreate(Sender: TObject);
 procedure Button1Click(Sender: TObject);
 private
 { Private declarations }
 procedure WMSysCommand(var Msg: TMessage); message WM_SYSCOMMAND;
 public
 { Public declarations }
 procedure CreateParams(var Params:
 TCreateParams); override;
 end;
var
 MainForm: TMainForm;
implementation
{$R *.DFM}
uses
 SubForm;
var
 SubForm: TSubForm;
procedure TMainForm.FormCreate(Sender: TObject);
begin
 SetWindowLong(Application.Handle, GWL_EXSTYLE,
 GetWindowLong(Application.Handle, GWL_EXSTYLE)or
 WS_EX_TOOLWINDOW and not WS_EX_APPWINDOW);
end;
procedure TMainForm.CreateParams(var Params: TCreateParams);
begin
 inherited CreateParams(Params);
 Params.ExStyle := Params.ExStyle or WS_EX_APPWINDOW and not WS_EX_TOOLWINDOW;
end;
procedure TMainForm.WMSysCommand(var Msg: TMessage);
begin
 DefaultHandler(Msg);
end;
procedure TMainForm.Button1Click(Sender: TObject);
begin
 SubForm := TSubForm.Create(Application);
 SubForm.Show;
end;
end.
SubForm Unit
unit SubForm;
interface
uses
 Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;
type
 TSubForm = class(TForm)
 procedure FormClose(Sender: TObject; var Action: TCloseAction);
 private
 { Private declarations }
 public
 { Public declarations }
 procedure CreateParams(var Params: TCreateParams); override;
 end;
implementation
{$R *.DFM}
procedure TSubForm.CreateParams(var Params: TCreateParams);
begin
 inherited CreateParams(Params);
 Params.ExStyle := Params.ExStyle or WS_EX_APPWINDOW;
end;
procedure TSubForm.FormClose(Sender: TObject; var Action: TCloseAction);
begin
 Action := caFree;
end;
end.
Forms Delphi
