Class Access
in [Visual Basic]
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From: BeeJ on 8 Aug 2010 19:58 I have some ActiveX code, both EXE and DLL that I wrote. It all seems to work but I occasionally have a weird thing happen. The code runs through Class_Terminate before Class_Initialize. I do not see why but it may be because I am working in the IDE and maybe this app is not closing as I thought or does the Set cEntry = Me make a double instantiation? There is no Main module and this does not start, Class_Initialize, until the app is instantiated in the main program. This is one of the ActiveX that do not want to terminate. All the others do what they are supposed to. The entry class named 'Entry' has this: ' ================================================= Public Event DevStatus(sStatus As String) Private Sub Class_Initialize() Set cEntry = Me ' to allow access from ' modules back to this class Startup ' code in module End Sub 'Class_Initialize Private Sub Class_Terminate() On Error GoTo Class_TerminateErr ShutDown ' code in module Set cEntry = Nothing Class_TerminateExit: Exit Sub Class_TerminateErr: Debug.Assert False Resume Class_TerminateExit End Sub 'Class_Terminate Friend Sub StatusMsg(sMsg As String) RaiseEvent DevStatus(sMsg) End Sub 'StatusMsg ' ================================================= The module mdlEntry has this: ' ================================================= Public cEntry As Entry Private Sub Msg(sMsg as String) cEntry.StatusMsg sMsg End Sub ' =================================================
From: ralph on 8 Aug 2010 21:29 On Sun, 08 Aug 2010 16:58:38 -0700, BeeJ <nospam(a)nowhere.com> wrote: >I have some ActiveX code, both EXE and DLL that I wrote. >It all seems to work but I occasionally have a weird thing happen. >The code runs through Class_Terminate before Class_Initialize. >I do not see why but it may be because I am working in the IDE and >maybe this app is not closing as I thought or does the Set cEntry = Me >make a double instantiation? Not a double instantiation - but does call Terminate. The Initialize event is fired only once when the object is created. Re-assigning to new references doesn't fire the event. However, the Terminate event is fired when the object is set to Nothing, when the last referenced object is 're-set' to a new reference using the Set/New, or when it is re-assigned to a new instance. -ralph
From: Tom Shelton on 8 Aug 2010 22:22 ralph pretended : > On Sun, 08 Aug 2010 16:58:38 -0700, BeeJ <nospam(a)nowhere.com> wrote: > >> I have some ActiveX code, both EXE and DLL that I wrote. >> It all seems to work but I occasionally have a weird thing happen. >> The code runs through Class_Terminate before Class_Initialize. >> I do not see why but it may be because I am working in the IDE and >> maybe this app is not closing as I thought or does the Set cEntry = Me >> make a double instantiation? > > <snip> > > However, the Terminate event is fired when the object is set to > Nothing, when the last referenced object is 're-set' to a new > reference using the Set/New, or when it is re-assigned to a new > instance. I think your trying to say that the terminate event fires when the last reference is released - correct? Just to be clear - doing a Set cEntry = Me would cause the reference count of the object pointed to by me to be incremented by one. And then when cEntry went out of scope, the reference count would be reduced by one - but, the terminate event would not fire... Since the Me reference is still arround. One cause of the described behavior maybe a circular reference.... That can definately cause a memory leak and an exe to hang around in memory rather then shutdown properly. Hard to know without seeing some code though.... -- Tom Shelton
From: BeeJ on 9 Aug 2010 12:17 Tom Shelton expressed precisely : > ralph pretended : >> On Sun, 08 Aug 2010 16:58:38 -0700, BeeJ <nospam(a)nowhere.com> wrote: >> >>> I have some ActiveX code, both EXE and DLL that I wrote. >>> It all seems to work but I occasionally have a weird thing happen. >>> The code runs through Class_Terminate before Class_Initialize. >>> I do not see why but it may be because I am working in the IDE and maybe >>> this app is not closing as I thought or does the Set cEntry = Me make a >>> double instantiation? >> >> > > <snip> > >> >> However, the Terminate event is fired when the object is set to >> Nothing, when the last referenced object is 're-set' to a new >> reference using the Set/New, or when it is re-assigned to a new >> instance. > > I think your trying to say that the terminate event fires when the last > reference is released - correct? > > Just to be clear - doing a Set cEntry = Me would cause the reference count of > the object pointed to by me to be incremented by one. And then when cEntry > went out of scope, the reference count would be reduced by one - but, the > terminate event would not fire... Since the Me reference is still arround. > > One cause of the described behavior maybe a circular reference.... That can > definately cause a memory leak and an exe to hang around in memory rather > then shutdown properly. Hard to know without seeing some code though.... On exiting, in Class_Terminate I do Set cEntry = Nothing So that should decrement.
From: Dee Earley on 10 Aug 2010 05:51
On 09/08/2010 17:17, BeeJ wrote: > On exiting, in Class_Terminate I do > > Set cEntry = Nothing > > So that should decrement. It will never decrement as cEntry still has a reference to it so the Terminate event will never be called. You must have an explicit "Close" method that unsets cEntry and allows it to terminate. -- Dee Earley (dee.earley(a)icode.co.uk) i-Catcher Development Team iCode Systems (Replies direct to my email address will be ignored. Please reply to the group.) |