[dba-VB] VB6: Object Reference

On 18 Apr 2003 at 9:07, Brett Barabash wrote:

> Here's one that is stumping me:
> I want to write an ActiveX DLL that contains: 
> - A class module to handle all properties/methods/events.
> - A form that is instantiated by the class, to display visual
> information to the user.
> 
> The form needs to interact with the class module to get at its
> properties/methods/events, so I thought that I should store an object
> reference in the form.  I tried the following code in the form:
> 
> Private WithEvents mobjSrcObj As clsMyClass
> 
> Public Property Set SourceObject (objSrcObj As clsMyClass)
>     Set mobjSrcObj = objSrcObj
> End Property
> 
> In the class module, I have the following code:
> 
> Private mfrmMyForm As frmMyForm
> 
> Public Sub Class_Initialize
>     Set mfrmMyForm = New frmMyForm
>     Set mfrmMyForm.SourceObject = Me
> End Sub
> 
> This works great, except for one small thing.  I cannot destroy the
> class instance by setting it to Nothing, because the Form it
> instantiated still has a reference to it.
> 
> There has to be a simple solution to this!

It sounds like you will need a "Tear Down" method of your class.

In your calss add:

Public Sub TearDown ()

  Set mfrmMyForm.SourceObject = Nothing
  Set mfrmMyForm = Nothing

End Sub

Then when you want to destroy the class you need to call your 
TearDown method before you set it to nothing

'Close and destroy

YourClassVariable.TearDown
Set YourClassVariable = Nothing

It's the same approach you have to take when you build Parent 
Properties for Classes.

--
Bryan Carbonnell - carbonnb at sympatico.ca
Age is a very high price to pay for maturity.