filter out nullable UserID LINQ

HI i want to filter the nullable items out of the groupPhonenumbers, but my linq query doesn't seem to work somehow.

the first method groupPhoneNumbers returns a list of a class with 3 items ( 3 phonenumbers).

results:

[0] --> UserId = "Test_Casper"

[1]---> UserId = ""

[2] --->UserId = ""

// Get all phonenumbers of the group.

var groupPhonenumbers = GroupLogic.GetGroupPhonenumbers(_log, request.requestId, request.sessionId, request.jSessionId, request.ServiceProviderId, request.GroupId, request.Filter, request.StartIndex, request.MaxItems).ToList();

groupPhonenumbers = groupPhonenumbers.Where(gr => (gr.UserId != null) || (gr.UserId != string.Empty)).ToList();

However when i do the where based on a linq query it still shows that twee records, so i;m doing something wrong.

I'm slightly confused about some of your question, but I'm going to take a stab at it. I'm assuming that your "results" collection contains the group phone numbers as well as a "UserId" that you want to test for empty values. Since "UserId" is nullable, is there any reason to expect an empty string as a value for some entries? I'd try the following...

In your first call to get the numbers, don't convert it to to a list yet, and put the "Where" clause on it like this:

var groupPhonenumbers = GroupLogic.GetGroupPhonenumbers(params).Where(gr => gr.UserId.HasValue);

I'd check your string values for empty spaces as well. If your checks for null and an empty string are failing, this might be the problem. Actually first just try replacing the checks with "string.IsNullOrWhiteSpace(phone)" and see if that fixes it.