Question

I am building my first few projects with ASP.NET MVC, and I have a list of items that come from 2 tables.

Using the nerd dinner example, this is my problem.

Lets say I want to have all the dinners, with all the rsvp information in a list on one page.

So it would go

dinnername1

rsvp1 rsvp2

dinnername2

rsvp1 rsvp2 rsvp3

Currently I’m using this linq to bring what I think is the correct data back

public IQueryable<Dinner> GetAllUserDinnersAndRSVPs(string userId)
    {
        return from dinner in db.Dinner
               from rsvp in db.RSVP
               where dinner.userId == userId
               where rsvp.userId == userId
               select dinner;
    }

This I think is bringing back the correct number of results, but because I am only bringing back the dinner type, the rsvp information doesn’t show up in the collection.

So I think what I need to do is build a custom Model (class?) which will store all the info from the dinners table and the rsvp table, called something like DinnerTask.cs

This will basically just have a load of properties for each of the columns of both of the tables, and will mean that I can sort the entire list in c# before using a foreach to render out to the page.

I guess the defination of the class would be something like this.

public class DinnersAndRSVPsModel
{


        public int DinnerId { get; set; }
        public string DinnerName { get; set; }
        rest of fields for table 1......

        public int RSVPId { get; set; }
        public int RSVPInfo { get; set; }
        rest of fields for table 2.......
}

I’m asking this question because I think this seems like I am doing this wrong, and hopefully someone can point me in the right direction for working with data like this.

I would really appreciate any examples of this including the linq query, class defination etc… Bonus points if you could help me with any of the sorting as well, but I think I should be able to work that out.

Thank you for any help.

Answer 1

I read Linq in Action to help me get to this solution, and then this post also helped me greatly

How do I group data in an ASP.NET MVC View?

The way I got this to work was by adding a custom type (class)

(excuse the bad naming conventions)

public class DinnerAndRsvpName
{
    public string Dinnername { get; set; }
    public string RSVPname { get; set; }

}

I then rewrite the linq query to this

return from dinner in db.Dinner
               join rsvp in db.RSVPs on Dinner.id equals RSVP.DinnerId into DinnerRsvp
               where dinner.userId == userId
               from rsvp in DinnerRsvp.DefaultIfEmpty()
               select new DinnerAndRsvpName
               {
                   Dinnername = goal.name,
                   RSVPname = rsvp == default(RSVPs) ? "No RSVP" : rsvp.name

               };

and then changed the model view to this

<ul>
 <% foreach (var group in Model.GroupBy(item => item.Dinnername)) { %>

<li><%= Html.Encode(group.Key) %>
 <ul>

 <% foreach (var item in group) { %>
   <li><%= Html.Encode(item.RSVPname) %></li>  
 <% } %>

 </ul>

  <% } %>