Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!stjhmc!p88.f15.n300.z1.fidonet.org!Lawson.English
From: Lawson.English@p88.f15.n300.z1.fidonet.org (Lawson English)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Neuron Data's Open Interface
Message-ID: <14492.28619076@stjhmc.fidonet.org>
Date: 21 Jun 91 05:11:51 GMT
Sender: ufgate@stjhmc.fidonet.org (newsout1.26)
Organization: FidoNet node 1:300/15.88 - Tucson Apple Core, Tucson AZ
Lines: 209

Gerrard Aissing writes in a message to All

GA> Hi! 
GA> I am new to Mac programming. I try to use the Think-C TCL to 
GA> create an application. At a certain point I want to use a dialog 
GA> to enter some data. After closing the dialog, the program crashes 
GA> in DoDeactivate(). There does not seem to be a Class for Modal 
GA> dialogs in TCL, bu using the standard routines seems to couse 
GA> a crash? So what should I do? Does anyone have experience in 
GA> implementing a class for modal dialogs? 
GA> Thanks.

I'm sorry that I have no way of uploading this to one of the regular sites,
as it makes me the resident "guru" on the subject. The TCL's don't handle 
dialogs
correctly. If you notice, when your program has no windows on the screen, 
there
should be no problem. When you have a window up, the TCL's somehow think that
the Dialog window is part of gDeskTop's window list, and try to send it 
messags
as it goes away... <ouch!>

The following code is based on Symantec tech support's suggestions:
The guts are the two follwing methods that deactivate the gDsktop before 
showing
the dialog, and reactivating it afterwards.

procedure CModalDialog.DeactivateTCLDeskAndShowDialog;
  var
   theDialogPtr: DialogPtr;
 begin
  theDialogPtr := itsDialogPtr;
  gDeskTop.Deactivate;
  BringToFront(theDialogPtr);
  ShowHide(theDialogPtr, TRUE);
 end;

 procedure CModalDialog.ActivateTCLDeskAfterHideDialog;
  var
   theDialogPtr: DialogPtr;
 begin
  theDialogPtr := itsDialogPtr;
  ShowHide(theDialogPtr, FALSE);
  SendBehind(theDialogPtr, WindowPtr(0));
  gDeskTop.Activate;
 end;


Below is my dialog class in all of its glory. CDialog is of type CObject.

itsDefaultItem is of type integer. itsFilterProc is a procPtr. itsDLOGid is
an integer. itsDialogPtr is a DialogPtr. You use the thing by evoking it with
either ".Go" or ".Run"

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
+



{ Copyright 1990 Lawson D. English }
{ Use freely, but remember where you got it when you become a hiring manager
}

unit CModalDialog;



interface

 uses
  TCL, DialogIntf;

implementation


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

  itsDefaultItem := aDefaultItem;
  itsFilterProc := aFilter;

 end;

{ * IResModalDialog * }
{ *}
{ *Initialize a ModalDialog object using a resource * }
{ * }
{ ** }
 procedure CModalDialog.IResModalDialog (aDLOGid: Integer; aFilter: procPtr;
aDefaultItem: Integer);
 begin
  itsDLOGid := aDLOGid;{ is there ever a reason to need the ID while running
?}
  itsFilterProc := aFilter;
  itsDefaultItem := aDefaultItem;

 end;

 procedure CModalDialog.free;
 begin
  DisposDialog(itsDialogPtr);

  inherited free;
 end;

 procedure CModalDialog.ProcureDialogPtr;
  var
   theDLOGid: Integer;
 begin
  theDLOGid := itsDLOGid;
  itsDialogPtr := GetNewDialog(theDLOGid, nil, WindowPtr(0));{ a dialog must
always be ionvisible when gotten }
 end;

 procedure CModalDialog.DeactivateTCLDeskAndShowDialog;
  var
   theDialogPtr: DialogPtr;
 begin
  theDialogPtr := itsDialogPtr;
  gDeskTop.Deactivate;
  BringToFront(theDialogPtr);
  ShowHide(theDialogPtr, TRUE);
 end;

 procedure CModalDialog.ActivateTCLDeskAfterHideDialog;
  var
   theDialogPtr: DialogPtr;
 begin
  theDialogPtr := itsDialogPtr;
  ShowHide(theDialogPtr, FALSE);
  SendBehind(theDialogPtr, WindowPtr(0));
  gDeskTop.Activate;
 end;

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

{**}
{ * Go * }
{ *}
{ *Generic RUN * }
{ * }
{ ** }
 procedure CModalDialog.Go;

 begin
  itsDefaultItem := 1;
  itsFilterProc := nil;
  ProcureDialogPtr;
  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(itsFilterProc, theDialogItem);
   DoModalDialogStuff;
  until (theDialogItem = itsDefaultItem);
  ActivateTCLDeskAfterHideDialog;
 end;

 procedure CModalDialog.DoModalDialogStuff;
 begin
{ override to do the "meat" of the dialog }
 end;
end.
 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 

Hope it helps...
 

 

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