NHibernate Error - Expression argument must be of type ICollection

• Posted by liammclennan on May 18, 2010
• 0 comments

The above error occurred when I executed a linq query using the following expression:

(s) => s.Book.Slug.Equals(bookslug) && ids.Contains(s.Id);

ids in this case is of type IEnumerable<Guid>. As indicated by the error message the fix is to change ids to ICollection<Guid>, then the query executes successfully.