Having Application.MainForm assigned seems not to be a problem here for showing another modeless form on the taskbar while minimizing the MainForm.
Project1.dpr:
program Project1;
uses
Forms,
Windows,
Unit1 in 'Unit1.pas' {MainForm},
Unit2 in 'Unit2.pas' {Form2};
{$R *.res}
var
MainForm: TMainForm;
begin
Application.Initialize;
Application.CreateForm(TMainForm, MainForm);
ShowWindow(Application.Handle, SW_HIDE);
Application.Run;
end.
Unit1.pas:
unit Unit1;
interface
uses
Windows, Messages, Classes, Controls, Forms, StdCtrls, Unit2;
type
TMainForm = class(TForm)
ShowForm2Button: TButton;
ShowForm2ModalButton: TButton;
procedure ShowForm2ButtonClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure ShowForm2ModalButtonClick(Sender: TObject);
private
FForm2: TForm2;
procedure ApplicationActivate(Sender: TObject);
procedure Form2Close(Sender: TObject; var Action: TCloseAction);
procedure WMSysCommand(var Msg: TWMSysCommand); message WM_SYSCOMMAND;
protected
procedure CreateParams(var Params: TCreateParams); override;
end;
implementation
{$R *.dfm}
procedure TMainForm.FormCreate(Sender: TObject);
begin
Visible := True; //Required only for MainForm, can be set designtime
Application.OnActivate := ApplicationActivate;
end;
procedure TMainForm.ApplicationActivate(Sender: TObject);
{ Necessary in case of any modal windows dialog or modal Form active }
var
TopWindow: HWND;
I: Integer;
begin
TopWindow := 0;
for I := 0 to Screen.FormCount - 1 do
begin
Screen.Forms[I].BringToFront;
if fsModal in Screen.Forms[I].FormState then
TopWindow := Screen.Forms[I].Handle;
end;
Application.RestoreTopMosts;
if TopWindow = 0 then
Application.BringToFront
else
SetForegroundWindow(TopWindow);
end;
procedure TMainForm.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
with Params do
begin
ExStyle := ExStyle or WS_EX_APPWINDOW;
WndParent := GetDesktopWindow;
end;
end;
procedure TMainForm.WMSysCommand(var Msg: TWMSysCommand);
begin
if Msg.CmdType = SC_MINIMIZE then
ShowWindow(Handle, SW_MINIMIZE)
else
inherited;
end;
{ Testing code from here }
procedure TMainForm.ShowForm2ButtonClick(Sender: TObject);
begin
if FForm2 = nil then
begin
FForm2 := TForm2.Create(Application); //Or: AOwner = nil, or Self
FForm2.OnClose := Form2Close;
end;
ShowWindow(FForm2.Handle, SW_RESTORE);
FForm2.BringToFront;
end;
procedure TMainForm.Form2Close(Sender: TObject; var Action: TCloseAction);
begin
Action := caFree;
FForm2 := nil;
end;
procedure TMainForm.ShowForm2ModalButtonClick(Sender: TObject);
begin
with TForm2.Create(nil) do
try
ShowModal;
finally
Free;
end;
end;
end.
Unit2.pas:
unit Unit2;
interface
uses
Windows, Messages, Classes, Controls, Forms;
type
TForm2 = class(TForm)
private
procedure WMSysCommand(var Msg: TWMSysCommand); message WM_SYSCOMMAND;
protected
procedure CreateParams(var Params: TCreateParams); override;
end;
implementation
{$R *.dfm}
procedure TForm2.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
with Params do
begin
ExStyle := ExStyle or WS_EX_APPWINDOW;
WndParent := GetDesktopWindow;
end;
end;
procedure TForm2.WMSysCommand(var Msg: TWMSysCommand);
begin
if Msg.CmdType = SC_MINIMIZE then
ShowWindow(Handle, SW_MINIMIZE)
else
inherited;
end;
end.
(Tested with D5 and D7 on XP and Win7.)
(And yes, you may flag this as being not an answer, because it isn't: There still is a MainForm. But I dó like to think this answers the question behind the question...)
