The inference I take from your answer, Luc (the answer seems "intuitively" correct to me), is that you could then iterate MyCollections, and, for each Collection in MyCollection, test for the presence of a specifc object using 'Contains. This solution also seeming to allow for the idea that you could also, then ... in the case of an object being a member of more than one Collection ... return a List of all Collections it was a member in, as well. However, I do think the OP's code is pretty weird. If you are going to add any type of object to a collection: that would seem to indicate a need to me for a generic (even "dynamic," late-bound ?) solution. thanks, Bill
"It is the mark of an educated mind to be able to entertain a thought without accepting it." Aristotle