From: Tim_Gooch@mm.cobb.ziff.com
Subject: Re: [delphi] HPrevInst
Date: Thu, 20 Jul 1995 09:30:14 -0500 (EST)
 
>> How do I set the application to make use of this.
 
Try this in the project source file:
 
====================================================
{usual stuff at the top of the project source file
var hwnd: Word;
 
begin
  if hPrevInst = 0 then
  begin
    Application.CreateForm(TForm1, Form1);
    Application.Run;
  end
  else
  begin
    hwnd := FindWindow('TForm1', nil);
    if (not IsWindowVisible(hwnd)) then
    begin
      ShowWindow(hwnd, sw_ShowNormal);
      PostMessage(hwnd, wm_User, 0, 0);
    end;
    else
      SetWindowPos(hwnd, HWND_TOP, 0,0,0,0,
        SWP_NOSIZE or SWP_NOMOVE);
  end;
end.
====================================================
 
In the form's PAS file add a message response function for the wm_User
message.
 
====================================================
{in the form declaration}
public
  procedure WMUser(var msg: TMessage); message wm_User;
 
{in the implementation section}
procedure TForm1.WMUser(var msg: TMessage);
begin
  Application.Restore;
end;
====================================================
 
(This tip courtesy of Marco Cantu')
 
Tim Gooch
 
Editor-in-chief
 - Borland C++ Developer's Journal
 - Delphi Developer's Journal