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Question

I have this query and I get the error in this function:

var accounts = from account in context.Accounts
               from guranteer in account.Gurantors
           


        

Answer 1

It appears that you're calling DateLastUpdated from within an active query using the same EF context and DateLastUpdate issues a command to the data store itself. Entity Framework only supports one active command per context at a time.

You can refactor your above two queries into one like this:

return accounts.AsEnumerable()
        .Select((account, index) => new AccountsReport()
        {
          RecordNumber = FormattedRowNumber(account, index + 1),
          CreditRegistryId = account.CreditRegistryId,
          DateLastUpdated = (
                                                from h in context.AccountHistory 
                                                where h.CreditorRegistryId == creditorRegistryId 
                              && h.AccountNo == accountNo 
                                                select h.LastUpdated).Max(),
          AccountNumber = FormattedAccountNumber(account.AccountType, account.AccountNumber)
        })
        .OrderBy(c=>c.FormattedRecordNumber)
        .ThenByDescending(c => c.StateChangeDate);

I also noticed you're calling functions like FormattedAccountNumber and FormattedRecordNumber in the queries. Unless these are stored procs or functions you've imported from your database into the entity data model and mapped correct, these will also throw excepts as EF will not know how to translate those functions in to statements it can send to the data store.

Also note, calling AsEnumerable doesn't force the query to execute. Until the query execution is deferred until enumerated. You can force enumeration with ToList or ToArray if you so desire.