Straight out of the Delphi manual (the application creates a global variable automatically as the form's name when you create a new form):
Put this in the form's OnClose event: MyForm.Free; MyForm := nil; To create it (from anywhere): If MyForm <> nil Then MyForm := TMyForm.Create(mainForm) (I always make the mainform the owner unless it's got an obvious child relationship to something else, that way it always gets freed during a GPF situation) If you create more than one, you can make sure you've freed them all by iterating through the Screen.Forms variable looking for that class type: For i := 0 to Screen.Forms.count-1 do If Screen.Forms[i] is TMyform then MyForm.close; See the demo's example under the folder: demos/db/MastApp. In fact, that application has an example of many useful tips to use in your own app. Dave --- "Jamie L. Mitchell" <[EMAIL PROTECTED]> wrote: > Hello all: > > I remember seeing a tip from ... somewhere on this > issue. I cannot > seem to dig it up now. > > I would like to have a global variable for a form: > > frmGlobal: TfrmGlobal; > > I would like to instantiate it from any place: > > frmGlobal := TfrmGlobal.Create(Application); > > and show it as a non-modal form: > > frmGlobal.Show; > > When I am done with the form, I would like to close > it and free it up. > Of course, the problem with this is that, at a > later date, I may want > to create it again. To avoid a memory leak, I > clearly would not want > to create a new instance if the existing instance > still exists. I > could use: > > If (Assigned(frmGlobal)) Then ... > > except that assigned merely asks the variable, "are > you NIL?" Since > merely freeing the variable does not set it to NIL, > the system thinks > it is still there. > > Since the form could be created anywhere, and the > form should be > deleted when it is closed, the best way to deal with > it would seem to > be figuring out a way to free the form and set the > global variable to > NIL from the OnDestroy event. I have had a number > of problems doing > this (chicken or egg problem.) A lot of AV's come > out of > experimenting with this. > > Does anyone have a good solution to how to free and > NIL [the global > variable] form from inside itself? > > Thanks > jamie > > > ____________________________________________________________________________________ 8:00? 8:25? 8:40? Find a flick in no time with the Yahoo! Search movie showtime shortcut. http://tools.search.yahoo.com/shortcuts/#news
