Possible Ge.Application bug in Mechanical 2005

Can anyone duplicate this behavior in Autocad Mechanical 2005 VBA/VB?

Sub test()
Dim GEAPP As GeApplication
Dim Point1 As GePoint
Dim Point2 As GePoint
Dim Var1 As Double

Set GEAPP = ThisDrawing.Application.GetInterfaceObject("Ge.Application")
Set Point1 = GEAPP.Point(0, 0, 0)
Set Point2 = Point1
Point2.X = 1: Point2.Y = 3
Var1 = Point1.X 'Point1.X value takes on the value of Point2.X - This should not happen
Var1 = Point1.Y 'Point1.Y value takes on the value of Point2.Y - This should not happen
End Sub

In my programming experience, setting Point2 = Point1 does not mean the same thing as setting Point1 = Point2. However, in my example, this is what is happening. If you can reproduce this behavior then this DLL has a HUUUUUGE problem.

Darren

 

If no one can duplicate what you described, than that would be a big
problem. Yes, your code behaves exactly it should. Here Point1 and Point 2
are merely two variable that pointing to the same GePoint object created
with the code GEAPP.Point(0,0,0). What happens in your code is something
like this:

Dim Point1 As GePoint
Dim Point2 As GEPoint

The declared two VARIABLEs (not object itself) are just used as reference to
object of GePoint type (class). They sit in memory and will hold memory
addess of GePoint object as their value, but right now, they hold nothing.

Set Point1=GEAPP.Point(0,0,0)

Here, GETAPP.Point(0,0,0) creates an instance of GePoint object and the
object instance take some memory itself, then Point1 variable takes the
object instance's memory address as its value. The object instance can only
be reached through reference varaible. That is, if you want to get to an
instance of an object, you look at a reference variable, the reference
variable points to you where the object instance is, 'cause it hold the
object instance's address.

Set Poin2=Point1

Now you make Point2 hold the same address value as Point1. Therefore, you
can do the same thing to that object instance through either Point1 or
Point2, 'cause they both refer to the same object instance.

So often, people confuse object variable and object instance, mistakenly
thinking Dim A As Something and Dim B As Something make two objects. No they
don't. They are only object variables ready to point to an object instance.
On the other hand, object instnace can only be reached through reference
variable, if no reference pointing to an object instnace, the object
instance will be destroyed by system.

same thing as setting Point1 = Point2. However, in my example, this is what
is happening. If you can reproduce this behavior then this DLL has a
HUUUUUGE problem.