creating a class within a class and returning data from database

Question

I created a class within a class so it could be an alternative to writing 3 different methods calling to the database- so i created a class with related items and now when i try to build i get the error Cannot implicity convert type System.collections.generic.list<anonymousType#1> to class that i created StudentDocuments and when i click on the error it directs me to the return subs statement.

public class  StudentDocuments
    {
        public Guid DocID {get; set;}
        public string Assignment {get; set;}
        public DateTime Submitted {get; set;}
        public string Student {get;set;}
    }




public StudentDocuments GetStudentSubmissionGrid(Guid usr, Guid lib)
    {
        using (var dc = new DocMgmtDataContext())
        {
            var subs = (from doc in dc.Documents
                        join u in dc.Users on doc.OwnedByUserID equals u.ID
                        where doc.OwnedByUserID == usr && doc.LibraryID == lib
                        select new { 
                            DocID = doc.ID, 
                            Assignment = doc.Library.Name, 
                            Submitted = doc.UploadDT,
                            Student = u.FullName
                        })
                .OrderByDescending(c => c.Submitted).ToList();
            return subs;
        }
    }

Hamlet Hakobyan · Accepted Answer · 2013-03-14 21:50:05Z

3

You create anonymous type your LINQ. Instead you must create the specific type object list according your return type.

Use this:

select new StudentDocuments{ 
                               DocID = doc.ID, 
                               Assignment = doc.Library.Name, 
                               Submitted = doc.UploadDT,
                               Student = u.FullName
                           }

and declare your method as:

public List<StudentDocuments> GetStudentSubmissionGrid(Guid usr, Guid lib)

You can also return IEnumerable<StudentDocuments> instead of list.

UPDATE

var subs = (from doc in dc.Documents
                    join u in dc.Users on doc.OwnedByUserID equals u.ID
                    where doc.OwnedByUserID == usr && doc.LibraryID == lib
                    orderby doc.UploadDT descending
                    select new StudentDocuments
                     { 
                        DocID = doc.ID, 
                        Assignment = doc.Library.Name, 
                        Submitted = doc.UploadDT,
                        Student = u.FullName
                     }).AsEnumerable().ToList();

edited Mar 14, 2013 at 21:50

answered Mar 14, 2013 at 21:27

Hamlet Hakobyan

33.5k6 gold badges55 silver badges70 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Masriyah Over a year ago

Thanks i think this will work but now it is telling me that i cannot implicity convert type iqueryable studentDocument to a list and that i might be missing a cast.

Colin DeClue Over a year ago

As an aside, you might want to think about having the GetStudentSubmissionGrid function return an IEnumerable, rather than returning a List. The benefit of this is that if you use LINQ further up to select a smaller list, it'll save some database work. (totally unrelated to answering the question, though).

Masriyah Over a year ago

@ColinDeClue advise considered and changed from List to IEnumerable thanks for explanation.

Collectives™ on Stack Overflow

creating a class within a class and returning data from database

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related