CODEWITHSUNDEEP
c#asp.net-mvclinqvisual-studio
djblois
djblois

Reputation: 815

Pull field from another table in MVC

am just learning MVC and this is my first project. What I am creating is a help desk for my company. Right now I am working on the Add Tickets.

The way I am trying to get it to work is we have a ticket category like 'Microsoft Office' that a user chooses. Each category has a Technician attached to it. So when the user chooses the category it is supposed to autoassign the technician. Here is the code I currently have:

public ActionResult Create(NewTicket newTicket)
    {
        Ticket ticket = new Ticket();
        TicketNote ticketNote = new TicketNote();

        try
        {
            Guid ticketGuid = System.Guid.NewGuid();

            //Add Ticket
            ticket.TicketId = ticketGuid;
            //ticket.TicketNumber = 
            ticket.CategoryId = newTicket.CategoryId;
            ticket.OpenUserId = new Guid("999600FC-709E-4463-84AD-D26894BABB54");
            ticket.OpenDate = DateTime.Now;
            ticket.TechnicianId = from c in db.Categories
                                  where c.CategoryId == newTicket.CategoryId
                                  select c.PrimaryTechnicianId;
            ticket.TicketStatusId = new Guid("00000000-0000-0000-0000-000000000000");
            //ticket.CloseDate = DateTime.Now;
            tickets.Insert(ticket);
            tickets.Commit();

            //Add Ticket Note
            ticketNote.TicketNoteId = System.Guid.NewGuid();
            ticketNote.TicketId = ticketGuid;
            ticketNote.TicketNoteDate = DateTime.Now;
            ticketNote.Note = newTicket.TicketNote;
            ticketNotes.Insert(ticketNote);
            ticketNotes.Commit();

            return RedirectToAction("Index");
        }
        //catch(Exception ex)
        catch
        {
            return View();
        }
    }

The issue I am having is particular on this line (the rest works):

ticket.TechnicianId = from c in db.Categories
                                  where c.CategoryId == newTicket.CategoryId
                                  select c.PrimaryTechnicianId;

The error I keep getting is 'Error 1 Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Guid' on the select statement in the above line

Upvotes: 1

Views: 536

Answers (2)

Callum Linington
Callum Linington

Reputation: 14417

Should you be overwriting the TechnicianId?

ticket.TechnicianId = from c in db.Categories
                                  where c.CategoryId == newTicket.CategoryId
                                  select c.PrimaryTechnicianId;
ticket.TechnicianId = new Guid("00000000-0000-0000-0000-000000000000");

The select just says which fields to pull out of the category object but will still return you an IQueryable<T>. In order to get Guid, you need to call .First() or .Single() afterwards to get 1 object out of the IQueryable<T>.

I advise calling .Single() because if you have a list of categories with more than 1 CategoryId then there is an error.

First() will bring you back a item from a list. Single() expects there to be only one item , if there isn't it will throw an error.

I recommend you read my answer to this question

Upvotes: 0

cuongle
cuongle

Reputation: 75316

I believe, this LINQ:

 from c in db.Categories where c.CategoryId == newTicket.CategoryId
                       select c.PrimaryTechnicianId;

will return IEnumerable, so in order to assign to ticket.TechnicianId, you should continue to call First or Single, something like this:

ticket.TechnicianId = (from c in db.Categories
                              where c.CategoryId == newTicket.CategoryId
                              select c.PrimaryTechnicianId).Single();

Upvotes: 1

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