Question

Im writing DLL for one project, I just started using LINQ to SQL and after moving all methods to this new dll. I disovered that I can’t acess DataContext because it was disposed, I understand why but I’m not sure how I can acess results of query for my main project method so:

My method in DLL

 public static IEnumerable<Problem> GetProblemsNewest(int howMuch)
        {
            using (ProblemClassesDataContext context = new ProblemClassesDataContext())
            {
                var problems = (from p in context.Problems orderby p.DateTimeCreated select p).Take(howMuch);

                return problems;
            }
        }

Calling it:

IEnumerable<Problem> problems = ProblemsManipulation.GetProblemsNewest(10);
//Error can't acess it because it was disposed..

This is just first method, I have larger ones so I really need a way to do this. There must be a way to use LINQ to SQL in DLL? I know I can do something Like .ToList or .ToArray but then I wouldn’t be able to acess row properties directly and would have to reference it as problem[0],problem[1] etc. which is even more messy than having tone of code in main project.

Answer 1

After you are outside of the using statement the context is automatically disposed, so when the IEnumerable is actually enumerated the context is already disposed.

Therefore you need to tell Linq that it should go ahead and actually retrieve the values from the DB while your inside of your using statement. You can do so via ToList() or ToArray (or others).

See the updated code:

public static IList<Problem> GetProblemsNewest(int howMuch)
{
    using (ProblemClassesDataContext context = new ProblemClassesDataContext())
    {
        var problems = (from p in context.Problems orderby p.DateTimeCreated select p).Take(howMuch);

        return problems.ToList();
    }
}