Update object in foreach loop - linq

Question

I am using EF4/LINQ for the first time and have run into an issue. I am looping thru the results of a LINQ query using a foreach loop as follows:
private static void OnTimedEvent(object source, ElapsedEventArgs e)
{
CallOutcomeSubmission los = new CallOutcomeSubmission();
client = connectToService();
try
{
using (var context = new CallOutcomeContext())
{
// List of available actions
private static string ACTION_CALL_ATTEMPT = "Call Attempt";
DateTime oneDayAgo = DateTime.Now.AddHours(-24);
var query = from co in context.T_MMCallOutcome
join ca in context.T_Call on co.CallID equals ca.CallID
join lv in context.T_LeadVendorEmailHeader on co.LeadVendorEmailID equals lv.LeadVendorEmailID
where co.EnteredOn > oneDayAgo && co.MMLeadActionID == null
select new
{
co.CallOutcomeID,
co.CallID,
co.LeadVendorEmailID,
MMLeadID = lv.email_text,
ca.OutcomeID,
lv.FranchiseNumber,
co.MMLeadActionID,
co.LeadAction
};
// if any results found for query
if (query.Any())
{
foreach (var call in query.ToList())
{
// if the franchise exists
if (client.FranchiseExists(int.Parse(call.FranchiseNumber)))
{
switch (call.OutcomeID)
{
case 39: // Not Answered
call.LeadAction = ACTION_CALL_ATTEMPT;
break;
case 43: // Remove from Call List
break;
default: // If the OutcomeID is not identified in the case statement
break;
} // switch
}
else
{
los.eventLog.WriteEntry("CallOutcomeSubmission.OnTimedEvent: No franchise found with franchise ID " + call.FranchiseNumber);
}
// Save any changes currently on context
context.SaveChanges();
} // foreach
}
// if no results found from query write system log stating such
else
{
los.eventLog.WriteEntry("CallOutcomeSubmission.OnTimedEvent: No new entries found");
}
} // using
client.Close();
}
catch (System.TimeoutException exception)
{
los.eventLog.WriteEntry("CallOutcomeSubmission.OnTimedEvent:" + exception.ToString());
client.Abort();
}
catch (System.ServiceModel.CommunicationException exception)
{
los.eventLog.WriteEntry("CallOutcomeSubmission.OnTimedEvent:" + exception.ToString());
client.Abort();
}
}
When I try to do the assignment:
call.LeadAction = ACTION_CALL_ATTEMPT;
I get a build error of
Property or indexer 'AnonymousType#2.LeadAction' cannot be assigned to -- it is read only
I can't seem to find anything on this specific error doing a Google search and am not sure what I am doing wrong. Is it because the original query contains a join?
How can I do the assignment of call.LeadAction within the foreach loop?
I would also like to know if there are design issue withe way I have written the query or performed any of the operations since this is my first foray into EF/LINQ.

Answer 1

You're creating a new anonymous type - with the Linq joins and then trying to set that value. What you're really wanting to do, is update the call's LeadAction correct?
How would EF know to translate your new query back to an entity so it can go back to the database? It would have to go through alot of hoops, and it's not capable of that.
What you could do, is retrieve the Call from your database and set the LeadAction that way - I'm using Find, assuming that CallID is your PK:
case 39: // Not Answered
var thisCall = context.T_Call.Find(call.CallID)
thisCall.LeadAction = ACTION_CALL_ATTEMPT;
break;