We help IT Professionals succeed at work.

Check out our new AWS podcast with Certified Expert, Phil Phillips! Listen to "How to Execute a Seamless AWS Migration" on EE or on your favorite podcast platform. Listen Now

x

Modal dialog not modal

cadenza
cadenza asked
on
Medium Priority
868 Views
Last Modified: 2010-04-04
In my app I create a dialog which I show with the ShowModal method.
After the dialog shows, a procedure is started (an other dialog method) where I run a loop which contains Application.ProcessMessages. Now the dialog no longer is modal: my app reacts to all other events, something I don't want. How can I show this dialog modal and still call Application.ProcessMessages? (I don't want to disable all controls of my main window to simulate a modal dialog). Or is this simply contradictory?

Wim
Comment
Watch Question

Commented:
Unlock this solution and get a sample of our free trial.
(No credit card required)
UNLOCK SOLUTION

Commented:
Another thing would be to place your procedure in a seperate thread.

Author

Commented:
Hi Rick and d003303,

HandleMessage nor a separate thread will do what I want. The app will still react on all messages, including messages sent to e.g. the buttonbar of my main form. What I want is that only the messages sent to my modal dialog (or its child controls) are handled. The messages relevant to me are: pressing the close button, scrolling a stringlist and some timer messages.

What I initially had hoped was that by showing the dialog modal, windows/delphi would ignore all messages sent to my app but not to the dialog.

More and more I get the feeling the only way to get this effect is to disable all controls of the main form (which is th only visible part of the app besides the dialog at the moment the dialog is shown)...

Commented:
What happens if you only use the ShowModal method and no ProcessMessages loop ? Like

MyDialog := TMyDialog.Create(Self);
MyDialog.Init;
if MyDialog.ShowModal = mrOK
 then UserPressedOK
 else UserPressedCancel;
MyDialog.Free;

Slash/d003303

Commented:
I'm a little confused on the behavior that you are trying to get...like Slash/d003303 shows...if you just place it in Showmodal...this is the default behavior of Delphi...if that's not what you want then you can use this procedure to enable and disable all your children...Just feed the procedure your Forms...and it should disable all it's controls...and also do the reverse...

procedure EnableControls(Enabled: boolean; Control: TWinControl);
var
  i: integer;
begin
  for i:= 0 to Control.ControlCount -1 do
    if ((Control.Controls[i]) is TControl) then
      if ((Control.Controls[i]) is TWinControl) and (TWinControl(Control.Controls[i]).ControlCount > 0) then
        EnableControls(Enabled,TWinControl(Control.Controls[i]))
      else
        TControl(Control.Controls[i]).Enabled := Enabled;
end;

Rick

Commented:
...some cosmetics:

procedure TForm_Progress.VisualFeedback(Sender: TObject);
begin
  with ProgressThread do
   begin
     ProgressBar1.Position := Trunc(100 / TotalCount * Position);
     Label_Progress.Caption := Format('%d  of %d processed', [TotalCount, Position]);
   end;
end;

procedure TForm_Progress.FormShow(Sender: TObject);
var SaveCursor : TCursor;
begin
  SaveCursor := Screen.Cursor;
  Screen.Cursor := crHourGlass;
  StartThread;
  Screen.Cursor := SaveCursor;
end;

Slash/d003303

Commented:
oops, sorry, wrong thread :-|

Author

Commented:
Rick & Slash,

I use the dialog to measure and present data from external equipment. I need a timer for time-out etc., so I need to call ProcessMessages once in a while to be able to catch the timer event. (this is reason 1 I need to call ProcessMessages)

 I can not put the loop in the OnShow event handler, since that would not show the dialog (and my measurements would not be shown). Therefor I send a user message to the dialog from the OnShow event handler. In the handler of the user message I put my measurement loop. This is handled after showing the dialog. If I would not call ProcessMessages in the loop, the click of the close button would not be handled. (reason 2).

If I don't call ProcessMessages, I have a modal dialog which can not be closed anymore and the timer event goes unnoticed. If I do call ProcessMessages, the dialog becomes modeless, effectively.

I think the only solution is Ricks disabling of all child controls, so I'll give him the points.

Both Rick and Slash many thanks for your contributions!

Wim

Commented:
Note...instead of watching for all the messages...you could have your timer...kickoff it's own personal message(using PostMessage and Wm_User)...that you watch for in your HandleMessage loop in your dialog...

Rick

Author

Commented:
Uhh, I think you may be right. Sounds quite complicated, though. And I'll have to do the same trick with some other components, like the close button? It seems to me that following your other suggestion with the recursive disableing of child controls is more straightforward to program.

I think I'll go for the easy solution now (disabling), keeping in mind what you wrote last, and try that later, when I have more time (instrument i/o always takes a lot of time to get right).

Thanks again,

Wim

Commented:
mmh, what about the following thought:
unit _tempform;

interface

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

type
  TForm_Temperature = class(TForm)
    Button1: TButton;
    ProgressBar1: TProgressBar;
    Label1: TLabel;
    Label2: TLabel;
    ProgressBar2: TProgressBar;
    Label3: TLabel;
    ProgressBar3: TProgressBar;
    Timer1: TTimer;
    procedure Timer1Timer(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form_Temperature: TForm_Temperature;

implementation

{$R *.DFM}

procedure TForm_Temperature.Timer1Timer(Sender: TObject);
begin
  // get measuer values form whatever API
  // just fake here
  ProgressBar1.Position := ProgressBar1.Position + Trunc(Random(20) + 0.6) - 10;
  ProgressBar2.Position := ProgressBar2.Position + Trunc(Random(20) + 0.6) - 10;
  ProgressBar3.Position := ProgressBar3.Position + Trunc(Random(20) + 0.6) - 10;
end;

procedure TForm_Temperature.FormShow(Sender: TObject);
begin
  Timer1.Enabled := true;
end;

end.

// form code

object Form_Temperature: TForm_Temperature
  Left = 200
  Top = 108
  BorderStyle = bsDialog
  Caption = 'Temperatures'
  ClientHeight = 127
  ClientWidth = 258
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OnShow = FormShow
  PixelsPerInch = 96
  TextHeight = 13
  object Label1: TLabel
    Left = 176
    Top = 12
    Width = 69
    Height = 13
    Caption = 'Temperature 1'
  end
  object Label2: TLabel
    Left = 176
    Top = 36
    Width = 69
    Height = 13
    Caption = 'Temperature 2'
  end
  object Label3: TLabel
    Left = 176
    Top = 60
    Width = 69
    Height = 13
    Caption = 'Temperature 3'
  end
  object Button1: TButton
    Left = 172
    Top = 92
    Width = 75
    Height = 25
    Caption = '&Close'
    Default = True
    ModalResult = 2
    TabOrder = 0
  end
  object ProgressBar1: TProgressBar
    Left = 12
    Top = 12
    Width = 149
    Height = 13
    Min = 0
    Max = 100
    Position = 50
    TabOrder = 1
  end
  object ProgressBar2: TProgressBar
    Left = 12
    Top = 36
    Width = 149
    Height = 13
    Min = 0
    Max = 100
    Position = 50
    TabOrder = 2
  end
  object ProgressBar3: TProgressBar
    Left = 12
    Top = 60
    Width = 149
    Height = 13
    Min = 0
    Max = 100
    Position = 50
    TabOrder = 3
  end
  object Timer1: TTimer
    Enabled = False
    Interval = 100
    OnTimer = Timer1Timer
    Left = 12
    Top = 92
  end
end

Slash/d003303

Commented:
Slash...

I think you posted to the wrong thread again....

Rick
Bought this Q
Unlock the solution to this question.
Thanks for using Experts Exchange.

Please provide your email to receive a sample view!

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.