Re: ATL/COM memory management

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From: Jag Man (Jag_Man653R-E-MOVE_at_hotmail.com)
Date: 05/10/04

  • Next message: Jag Man: "Re: ATL/COM memory management" 
    Date: Mon, 10 May 2004 08:40:45 -0700

    Simon,

    > > Dim myObj As myClass(10)
    > > in the declarations section of a Module, but it is not accepted.
    >
    > No, the client will create ten instances of the object by making ten calls
    > to the class factory.

    I was not trying to indicate 10 instances of the class. Rather, I was trying
    to say
    one instance of the class, but with that instance having a member array
    allocated
    to be size 10.

    > > If it can't be done this way, how does one get the size to allocate some
    > > form of an array
    > > in a constructor or FinalConstruct()?
    >
    > I'm not sure what you are trying to do here. The array (or a
    > pointer/reference to it) should be a *member* of the coclass, which then
    > defines indexed properties to access it.
    >If desirable, make a separate
    > "container" class that just wraps the array, and in your other class
    define
    > properties which are typed to this separate class. (This also has the
    > advantage that the separate class is likely to me more reusable, and then
    > you can also define the NewEnum property on it to get "for each" style
    > enumeration.

    Yes, the array is to be a class member. Clearly, that array has to have
    memory allocated
    for it. In C++ one would make the class member a pointer, then allocate in
    the constructor
    using a parameter:

    myClass::myClass(int size)
    {
          n = size;
         theArray = new long[n];
    }

    so that to instantiate one would write:

    myClass object(10); // creating one instance of myClass having an array size
    of 10.

    I am trying to do the equivalent of this in a COM to be used in VBA. What I
    am missing somehow
    is how the VBA tells the COM what size of array will be needed.

    Thanks for your patience!

    Ed

  • Next message: Jag Man: "Re: ATL/COM memory management"

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