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From: Lawson.English@p88.f15.n300.z1.fidonet.org (Lawson English)
Newsgroups: comp.sys.mac.programmer
Subject: What am I doing wrong?--modal dialog use crashes
Message-ID: <10529.282956F5@stjhmc.fidonet.org>
Date: 9 May 91 00:53:17 GMT
Sender: ufgate@stjhmc.fidonet.org (newsout1.26)
Organization: FidoNet node 1:300/15.88 - Tucson Apple Core, Tucson AZ
Lines: 188

Willy S. Liao writes in a message to All

WSL>  OK dokee, I have a problem that's driving me nuts. I'm sure 
WSL> I'm doing something wrong, but I don't know what it is...I'm 
WSL> using THINK C 4.04 with System 7.0f4 and the Think Class Library

The Think Class Libraries don't support dialogs directly (gDeskTop gets confused
and tries to send messages to the dialog window after it is gone).

The following class is based on the information supplied by Symantec Tech Support.
The key procedures are: 

DeactivateTCLDeskAndShowDialog;

and

ActivateTCLDeskAfterHideDialog;

which will prevent gDeskTop from getting an update while the dialog is around.

One does "myDialog.IResModalDialog (aDLOGid, aFilter, aDefaultItem);" followed
by  "myDialog.Go" (for generics) or "Run" (for more complicated dialogs) and
overrides the "DoModalDialogStuff" method to do the inner workings.

Caveat: only one ModalDialog should be "GO"-ing at a time...otherwise gDeskTop
might get confused. Never tried it with multiple dialogs, maybe it will work...

Hope it helps, source code released for public use by Lawson D. English.



******************************************************************************

{*****************************************************************************}
{** CModalDialog implements a generic Modal Dialog Class                   
**}
{** Copyright 1991 Lawson D. English (use at will but remember me as well) 
**}
{** From Symantec Tech Support suggestions.                                
**}
{**}
{*****************************************************************************}


unit CModalDialog;



interface

uses
TCL, DialogIntf;

implementation


{**}
{ * IModalDialog}
{ *}
{ *Initialize a ModalDialog object.}
{ *}
{ **}
procedure CModalDialog.IModalDialog (aFilter: procPtr; aDefaultItem: Integer);
begin

itsDefaultItem := aDefaultItem;
itsFilterProc := aFilter;


{ you would have to override here to create dialogs on-the-fly }
end;

{ * IResModalDialog * }
{ *}
{ *Initialize a ModalDialog object using a resource * }
{ * }
{ ** }
procedure CModalDialog.IResModalDialog (aDLOGid: Integer; aFilter: procPtr;
aDefaultItem: Integer);
begin
itsDLOGid := aDLOGid;
IModalDialog (aFilter, aDefaultItem);
end;

procedure CModalDialog.free;
begin
DisposDialog(itsDialogPtr);

inherited Free;
end;

procedure CModalDialog.ProcureDialogPtr;
var
theDLOGid: Integer;
begin
theDLOGid := itsDLOGid;
{ a dialog must always be invisible when gotten }
{ to avoid sending updates to gDeskTop, hence "WindowPtr(0)"}
itsDialogPtr := GetNewDialog(theDLOGid, nil, WindowPtr(0));
end;

procedure CModalDialog.DeactivateTCLDeskAndShowDialog;
var
theDialogPtr: DialogPtr;
begin
theDialogPtr := itsDialogPtr;
gDeskTop.Deactivate;        { we can't have gDeskTop active when }
BringToFront(theDialogPtr); { the dialog comes to the front }
ShowHide(theDialogPtr, TRUE);
end;

procedure CModalDialog.ActivateTCLDeskAfterHideDialog;
var
theDialogPtr: DialogPtr;
begin
theDialogPtr := itsDialogPtr;
ShowHide(theDialogPtr, FALSE);
SendBehind(theDialogPtr, WindowPtr(0)); { Hide the dialog before gDeskTop }
gDeskTop.Activate;                      { is activated }
end;

{**}
{ * SetDialogID}
{ *}
{ *For those times when you need to have a generic dialog with various IDs}
{ * and just say "Go"}
{ **}
procedure CModalDialog.SetDialogID (aDLOGid: integer);
begin
itsDLOGid := aDLOGid;
end;

{**}
{ * Go * }
{ *}
{ *Generic RUN using defaults of no procPtr and itemHit of 1 for RETURN * }
{ * }
{ ** }
procedure CModalDialog.Go;

begin
itsDefaultItem := 1;   { implements the generic "RETURN" default dialog}
itsFilterProc := nil;  { with no filterProc }

RunModalDialog;
free;
end;

{**}
{ * RunModalDialog}
{ *}
{ *Run ModalDialog object... NO! REally?}
{ *}
{ **}
procedure CModalDialog.RunModalDialog;
var
theDialogItem: Integer;
theFilterProc: ProcPtr;
theDLOGid: Integer;
begin
theFilterProc := itsFilterProc;

ProcureDialogPtr;
DeactivateTCLDeskAndShowDialog;

repeat
ModalDialog(theFilterProc, theDialogItem);
DoModalDialogStuff(theDialogItem);
until (theDialogItem = itsDefaultItem);
ActivateTCLDeskAfterHideDialog;
end;

procedure CModalDialog.DoModalDialogStuff(theDialogItem:Integer);
begin
{ needs to be overriden in your own dialog classe }
end;
end.




end.
*******************************************************************************
 

--  
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