LINQ SubmitChanges with join doesnt work

Question

I cannot get the data from adc to update to database. I am using LINQ2SQL dbml. I get no sql output from CAPcontext.Log, and Both tables have primary ID's I feel it is an issue with the join in the LINQ query but couldnt find anything on the web regarding it. Can someone point out what am I doing wrong?

   CAP_MDF_dataContextDataContext CAPcontext = new CAP_MDF_dataContextDataContext();

 public bool LoadCAPadultdaycare()
    {
        CAPcontext.Log = Console.Out;
        var adc = (from v in CAPcontext.AdultDayCares
                   join s in CAPcontext.States on v.state equals s.Name
                 select new CAPadultdaycare {
                     Avg = v.Avg,
                     City = v.city,
                     High = v.High,
                     Low = v.Low,
                     StateFullName = v.state,
                     StateAbbr = s.Code                     
                 }).ToList();

  foreach (var item in adc)
        { item.City = "some city";
             // updating more fields but omitted here
         }

 CAPcontext.SubmitChanges();
 return true;
}

My CAPadultdaycare class is...

 public class CAPadultdaycare
{
    public decimal? High { get; set; }
    public decimal? Low { get; set; }
    public decimal? Avg { get; set; }
    public string Zip { get; set; }   
    public string City { get; set; }
    public string StateAbbr { get; set; }
    public string StateFullName { get; set; }
}

score 0 · Answer 1 · answered Sep 15 '16 at 21:17

You are creating new CAPadultdaycare objects, which are not attached to your data Context and hence not submitted.

The following may work

var adc = (from v in CAPcontext.AdultDayCares
               join s in CAPcontext.States on v.state equals s.Name
             select v).ToList();

foreach (var item in adc)
    { item.City = "some city";
         // updating more fields but omitted here
     }

CAPcontext.SubmitChanges();

but this means you are pulling all columns from your database.

LINQ SubmitChanges with join doesnt work

1 Answers1