how to know if my linq query returns null

Question

I have this linq query :

var myQuery = from Q in myDataContext
          select Q.Name

and when I try to do this : listView.ItemsSource = myQuery

it sometimes throws an exception because there are no elements in myQuery

I tried many ways like : if(myQuery.count!=0) or if(myQuery.Any()) but nothing worked , so how can I determine if my Query return null ?

Answer 1

You can realise the result as a list:

var myQuery = (from Q in myDataContext select Q.Name).ToList();

Now you can check the number of items:

if (myQuery.Count > 0) ...

You could also use the Count() method on the original query, but then you would be running the query twice, once to count the items, and once to use them.