通过链接查询结束n + 1问题以连接多个表

Question

I have a Linq query that I currently pull out a table and then in the view I filter 5 joins down to a specific value. This as many of you know would greatly increase the amount of time for my view to load as for each record has to run its own individual query for each of the joins. I want to switch the joins in to the Linq query, so it is all in one query but I am having trouble.

Here is my controller code:

private IEnumerable<Ticket> FindTechTickets(Guid ticketStatusId)
{
       Guid g = Guid.Parse(Session["LoggedUserID"] as string);

       return db.Tickets
              .Include(t => t.TicketNotes)
              .Where(t => t.TechnicianId == g).Where(t => t.TicketStatusId == ticketStatusId)
              .OrderByDescending(t => t.TicketNumber)
              .ToList();

}

And here is my view code:

@foreach (var item in Model.OrderByDescending(m => m.TicketNumber))
{
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.TicketNumber)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.OpenDate)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.OpenUser.FullName)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Category.CategoryName)
        </td>
        <td>
            <div>
                @Html.DisplayFor(modelItem => item.TicketNotes.OrderBy(t => t.TicketNoteDate).Last().TicketNoteDate)
            </div>
        </td>
        <td>
            <div>
                @Html.DisplayFor(modelItem => item.TicketNotes.OrderBy(t => t.TicketNoteDate).Last().UserNote.FullName)
            </div>
        </td>
        <td>
            <div style="overflow:auto; width:300px;">
                @Html.DisplayFor(modelItem => item.TicketNotes.OrderBy(t => t.TicketNoteDate).First().Note)
            </div>
        </td>
        <td>
            @Html.ActionLink("Open/Edit", "EditTechTicket", new { id = item.TicketId, returnUrl = "TechOpenTickets", ViewBag.page})
        </td>
    </tr>
}

and here is my attempt at changing the Linq query:

var ts = 
          from t in db.Tickets
          Join tn in db.TicketNotes on t.TicketId equals tn.TicketId
          Where(t => t.TechnicianId == g).Where(t => t.TicketStatusId == ticketStatusId)
          OrderByDescending(t => t.TicketNumber)
          select new
          {

          }

The problem is am getting build errors on almost every line. Starting with the Join line.

This is the link that I am getting the information from:

Pulling out different columns from different tables using LINQ

Answer 1

1. It seems you're missing some parentheses.

2. Join is not the method you're looking for. It does something entirely different. You want Include .