The object disconnected from its clients !

Hi all !

This error raises in Autocad VBA (Autodesk Map 5 SP1) when I call:
Set oAcadLWPolyLine = oAcadEntity.Copy
It does NOT happen if I call "Thisrawing.PurgeAll" before !

Let me first explain what the VBA macro is doing :

The user selects an item in a listbox on a form. The drawing
(opened from a dwt), is "SavedAs" with a name that depends on the
users choice.
There are then 2 queries (Map queries) being run, which draw
entities on the drawing.

This is where I call ThisDrawing.PurgeAll.

Then, I open a selection Set with :
gpCode(0) = 8 : gpValue(0) = myLayer
oSelSet.Select acSelectionSetAll, , , gpCode, gpValue

I then loop through the SelectionSet and do things depending on
the entity's type :

For Each oAcadEntity In oSelSet
Select Case True
Case TypeOf oAcadEntity Is AcadLWPolyline
Set oAcadLWPolyline = oAcadEntity.Copy <- ERROR!!!
Case TypeOf oAcadEntity Is AcadPolyline
Set oAcadPolyline = oAcadEntity.Copy
Case Else
etc ....
End Select
Next oAcadEntity

I ran the macro step by step : oAcadLWPolyline is defined and
equals to nothing (the error raises on the first loop). The
SelectionSet is defined and filled with entities (lwpolylines and
lines, that's good). oAcadEntity's type is AcadLWPolyline.

I really don't understand what's going wrong here !
I need to remove the "PurgeAll", because there are a lot of empty
layers and unused text styles that I need to keep in the drawing.

Can someone help me on this ?

Thanks a lot !

Arnaud Lesauvage

 

You cannot execute the Copy method while iterating through a collection.

Joe

 

Thanks for your answer Joe.
Why does it work when I purge the drawing ?

 

I don't know. Does the routine work the first time through or the second?

Can you post the entire routine?

Joe
--

 

It's a "one shot" routine : it starts in a new drawing and inserts
everything that is needed. The PurgeAll is useless, but it makes
it works...

I can, but it's kind of huge... I'll post if you want to check for
yourself though !
For the moment, I worked around the problem by removing the
oAcadEntity.Copy as you suggested and by replacing it with
ThisDrawing.ModelSpace.AddLightWeightPolyline(oAcadEntity.Coordinates).
It works fine, but I am still very curious !

 

I found it odd as to why as Joe pointed out "You cannot execute the Copy method while iterating through a collection.".
This is the full help explanation "NOTE You cannot execute this method while simultaneously iterating through a collection. An iteration will open the work space for a read-only operation, while this method attempts to perform a read-write operation. Complete any iteration before you call this method.".
I would suggest you may be able to iterate the collection adding the items to an array of entities and then process the array. If that doesn't work either you may be able to iterate the collection adding the items handles to an array and then process the array using the HandleToObject method.

Regards - Nathan

 

You wouldn't have to go to the extreme of using handles. I can't replicate
your error on my setup, but I think all you would have to do would be to
replace your "For Each" with a "For i = 0 to ModelSpace.Count-1" type of
loop. This way, when new objects are added to ModelSpace, they will have
higher indices than the original count and won't get reprocessed by the
loop. With a "For Each" loop that makes copies, every time you think you're
getting one item closer to the end of ModelSpace, you're adding another
item... you're on a ModelSpace treadmill.

James

method while iterating through a collection.".

while simultaneously iterating through a collection. An iteration will open
the work space for a read-only operation, while this method attempts to
perform a read-write operation. Complete any iteration before you call this
method.".

to an array of entities and then process the array. If that doesn't work
either you may be able to iterate the collection adding the items handles to
an array and then process the array using the HandleToObject method.

 

The Count property will be queried on each iteration so the new objects
will be processed. Either assign the current value of the property to a
variable or use a different collection for the iterating; a selection
set or collection object, for example.

 

Arnaud is actually using a selection set. I think the note in the help may be referring to what your talking about in iterating the modelspace collection. In which case I don't think his problem is to do with the note from the help file.
Regards - Nathan

 

I think that the problem stems from this line:

Set oAcadLWPolyline = oAcadEntity.Copy

since the former is dimensioned as a AcadLWPolyline and the latter is
dimensioned as a AcadEntity, and the copy returns the same object as the
original.
Using this, with the oCopyEntity dimensioned as an AcadEntity works for
me....

Set oCopyEntity = oAcadEntity.Copy
Set oAcadLWPolyline = oCopyEntity

 

Hi Jeff,
Did he original code raise an error ?
(Set oAcadLWPolyline = oAcadEntity.Copy)

 

Indeed, I am using a Selection Set.
The NOTE in the documentation actually states that what I was
doing was wrong (i.e. using the "copy" method), but the error
message was really surprising !
A "good" error message could have stated that a write operation
could not be performed, for instance.
And furthermore, why can I write to the workspace (if I understand
the meaning of this word) using
ThisDrawing.ModelSpace.AddSomeKindOfEntity(), and not using
oAcadEntity.Copy ?

Arnaud