MDI Child Close Event

ntony
ntony used Ask the Experts™
on
I have an MDI application. I want to know if there is an event for child close.
i've tried :

  if Message.Msg=WM_MDIDESTROY then begin
     ShowMessage('Child closed');
  end else inherited WndProc(Message);

but it does not work. Can anyone tell me why?
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Top Expert 2004

Commented:
why not use the onClose.event of your MDIChild?

Author

Commented:
I have a list with child window so i need to delete the child when it will be closed.

Commented:

Is the childform really closed in your program.
You can try to write some codes in the two event:OnClose,OnDestroy.
Just like showmessage('c') in onclose;showmessage('d') in onDestroy.
You will find that when you close the Childform,only show "c" ;
When you add "action :=caFree" in OnClose,you will see "d";
So...maybe you will find the right answer.

I guess but not test the following code;
if Message.Msg=WM_Close then begin
     ShowMessage('Child closed');
  end else inherited WndProc(Message);
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Top Expert 2004

Commented:
you could notify the mainform in the onClose-event of your MDIChilds instead

may this possible for you?

Author

Commented:

huiyue i've used caFree on the child form.

Kretzschmar - i need a simple solution
Top Expert 2004

Commented:
how shows your list?
by classname or by formname?

Author

Commented:
is't a stringlist with objects TForm
Top Expert 2004
Commented:
well a sceleton

the main:

unit MDIChild_Notifys_Main_Main_u;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls,
  MDIChild_Notifys_Main_Child;  //uses the childUnit in the Interfacepart

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    FFormList : TstringList;
  public
    procedure RemoveFromList(AForm : TForm);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.RemoveFromList(AForm : TForm);
var i : integer;
begin
  i := FFormList.IndexOfObject(AForm);
  if i > -1 then
    FFormList.Delete(i);
  ShowMessage('Child removed.'+#10+'Remaining Childs: '+inttostr(FFormList.Count));
end;


procedure TForm1.FormCreate(Sender: TObject);
begin
  FFormList := TStringList.Create;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  FFormList.Free;
end;

procedure TForm1.Button1Click(Sender: TObject);
var f : Tform2;
begin
  f := Tform2.Create(self);
  FFormList.AddObject('AChild',f);
end;

end.

-----------------------

the child:

unit MDIChild_Notifys_Main_Child;

interface

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

type
  TForm2 = class(TForm)
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

uses
  MDIChild_Notifys_Main_Main_u;  //important-> uses in the implementation

procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  TForm1(Application.MainForm).RemoveFromList(self);
  action := caFree;
end;

end.

----

meikl ;-)

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