Form ansprechen während einer Bearbeitung

[Jens01]

In den Cindy-Komponenten habe ich ein ProgressPanel gefunden und das wie Folgt adaptiert.
Die Threadlösung ist derzeit etwas zu groß für mich.
Bei dieser Lösung frieren aber auch alle Fenster ein. Das Progressfenster zeigt aber die Bars an und der Button kann den Prozess canceln.

Delphi-Quellcode:

type
  TfrmProgress = class(TForm)
    pb2: TProgressBar;
    pb1: TProgressBar;
    btn1: TButton;
    procedure btn1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
  public
    IsCanceled: Boolean;
    function  ProcessMessages(var Msg: TMsg): Boolean; overload;
    procedure ProcessMessages; overload;
  end;

var
  frmProgress: TfrmProgress;

implementation

{$R *.dfm}

procedure TfrmProgress.ProcessMessages;
var
  Msg: TMsg;
  Cont: Boolean;
begin
  cont := ProcessMessages(Msg);

  while Cont do
    cont := ProcessMessages(Msg);
end;

procedure TfrmProgress.btn1Click(Sender: TObject);
begin
  IsCanceled := True;
end;

procedure TfrmProgress.FormShow(Sender: TObject);
begin
  pb1.Position := 0;
  IsCanceled := False;
end;

function TfrmProgress.ProcessMessages(var Msg: TMsg): Boolean;
var
  aHandle: HWND;
begin
  RESULT := false;
  if IsCanceled then
    EXIT;
  aHandle := 0;    // aHandle := FPanel.Handle doesn' t work if you click outiside the panel before clicking panel's cancel button ...

  if PeekMessage(Msg, aHandle, 0, 0, PM_REMOVE) then
  begin
    Result := True;

    if Msg.hwnd = btn1.Handle then
    begin
      Windows.TranslateMessage(Msg);
      Windows.DispatchMessage(Msg);
    end
    else if Msg.message = WM_PAINT then // !!! Only WM_PAINT message are not removed from queue          !!!
    begin                             // In order to go outside  while Cont do, we need to dispatch the message //
      Windows.TranslateMessage(Msg);
      Windows.DispatchMessage(Msg);
    end;
  end;
end;

Die Berechnungsschleife:

Delphi-Quellcode:

frmProgress.Show;
for i:= 0 to 1000
begin
  Berechnung;
  frmProgress.ProcessMessages;
  if frmProgress.IsCanceled then
    break;
end;
frmProgress.Close;