Why does .NET foreach loop throw NullRefException when collection is null?

Question

So I frequently run into this situation... where Do.Something(...) returns a null collection, like so:

int[] returnArray = Do.Something(...);
         


        

Answer 1

A foreach loop calls the GetEnumerator method.
If the collection is null, this method call results in a NullReferenceException.

It is bad practice to return a null collection; your methods should return an empty collection instead.