linq union of two lists

Question

I have an object model that contains a list of longs. I want to get the combined list of longs of two different instances. When I write this:

var MyCombinedList = TheObject1.ListOfLongs.Union(TheObject2.ListOfLongs);

I get an empty list. Note that sometimes TheObject2 can have an empty list.

What am I doing wrong?

Thanks.

Answer 1

Use Concat() this will concatenates two sequences. So try this instead :

var MyCombinedList = TheObject1.ListOfLongs.Concat(TheObject2.ListOfLongs);

Good Luck !!