MVC LINQ to SQL JOIN for custom type fails for strongly typed view

I have a simple data model of two tables, email and recipients, email can be sent to one or more recipients.

I set up a database with two tables, created a Linq to SQL repository, created controllers and a strongly typed view.

This works great when I want to select all records from the database

public IList<AllMailDetail> ListAll()
    {
        var allMail =
            from m in _datacontext.mail_receiveds
      join r in _datacontext.mail_recipients on m.DeliveryId equals r.DeliveryId
            select new AllMailDetail {
                                        DeliveryId = m.DeliveryId,
                                        MessageId = m.MessageId,
                                        SentFrom = m.SentFrom,
                                        FilePath = m.FilePath,
                                        FileName = m.FileName,
                                        SentDateTime = m.SentDateTime,
                                        ReceivedDateTime = m.ReceivedDateTime,
                                        Subject = m.Subject,
                                        SpamScore = m.SpamScore,
                                        IsSpam = m.IsSpam,
                                        SenderIP = m.SenderIP,
                                        Header = m.Header,
                                        SentTo = r.SentTo
                                      };

        return allMail.ToList <AllMailDetail>();
    }

      

        
        
        
      

    

Custom type class

public class AllMailDetail
{
    public int DeliveryId { get; set; }
    public int? MessageId { get; set; }
    public string SentFrom { get; set; }
    public string FilePath { get; set; }
    public string FileName { get; set; }
    public string SentDateTime { get; set; }
    public DateTime ReceivedDateTime { get; set; }
    public string Subject { get; set; }
    public byte? SpamScore { get; set; }
    public bool? IsSpam { get; set; }
    public string SenderIP { get; set; }
    public string Header { get; set; }
    public string SentTo { get; set; }
}

      

        
        
        
      

    

The controller simply pushes the content from the repository into a strongly typed view

public ActionResult Index()
    {
        return View(_repository.ListAll());
    }

      

        
        
        
      

    

In order to get only one record by mail from the database, I have the following code which accepts deliveryId

public IQueryable<AllMailDetail> GetMail(int? id)
    {
        var allMail =
            from m in _datacontext.mail_receiveds
            join r in _datacontext.mail_recipients 
            on m.DeliveryId equals r.DeliveryId
            where m.DeliveryId == id
            select new AllMailDetail
            {
                DeliveryId = m.DeliveryId,
                MessageId = m.MessageId,
                SentFrom = m.SentFrom,
                FilePath = m.FilePath,
                FileName = m.FileName,
                SentDateTime = m.SentDateTime,
                ReceivedDateTime = m.ReceivedDateTime,
                Subject = m.Subject,
                SpamScore = m.SpamScore,
                IsSpam = m.IsSpam,
                SenderIP = m.SenderIP,
                Header = m.Header,
                SentTo = r.SentTo
            };

        return allMail;
    }

      

        
        
        
      

    

And its controller code

public ActionResult Details(int? id)
    {       
        var mail = _repository.GetMail(id);

        if (mail == null)
            return View("NotFound");

        return View(mail);
    }

      

        
        
        
      

    

I was trying to display the output for one entry, also using a strongly typed view with Inherits = "System.Web.Mvc.ViewPage At the top of the aspx page, but I got the following error

The model item passed to the dictionary is of type "System.Data.Linq.DataQuery`1 [projectMail.Models.AllMailDetail]", but this dictionary requires a model item of type projectMail.Models.AllMailDetail.

I fixed this error after searching many times and found this post most helpful MVC LINQ to SQL Table Join Record Display

so my view is not heavily printed anymore and I create the page like this

<% foreach (projectMail.Models.AllMailDetail item in (IEnumerable)ViewData.Model)
    { %>

       ...items...

 <%  } %>

      

        
        
        
      

    

This works great, but it seems like a long way to go. The thing I cannot understand

• Why does the second query have to be IQueryable
• Why didn't it work when the performance was strictly printed
• How to do this to work with a strongly typed view
• This is the best way to work with unions in MVC using LINQ to SQL