Correct way to destroy a form and show another in Delphi

Question

Currently in my program I have a Startup form, and a Main form. The startup form shows for a second or two.

Right now, I have the following code within a timer:

  frmStartup.Destroy;

  frmMain := TfrmMain.Create(Self);
  frmMain.Show;

Right now, I'm not sure if this is the correct way to do it.. It works, but when calling application.Terminate(); I receive an access violation message, leading my to believe that I have done something wrong in the destruction of the startup form..

If anyone could show the the correct procedure for doing what I want (non-modally) It would be greatly appreciated.

Thanks in advance,

EDIT:

Thanks for all the feedback, I fixed my access violations by simply adding the code:

  Action := caFree;

Into the frmStartup.formClose method.

Answer 1

Don't create the frmStartup using Application.CreateForm. The first form created there becomes your application's main form, and if that's frmStartup you're destroying it outside Application knowledge.

Instead, use a normal Form.Create in your project source (.dpr) file:

var
  frmStartup: TfrmStartup;

begin
  Application.Initialize;
  Application.MainFormOnTaskBar := True;
  frmStartup := TfrmStartup.Create(nil);  // No owner assigned here!
  frmStartup.Show;
  frmStartup.Update;

  Application.CreateForm(TfrmMain, frmMain); // Let Application have this for main form
  // Delay here if needed
  frmfrmStartup.Free;
  Application.Run;
end.