Question

I am gathering data from a web-form with the code below:

secondContact.FirstName = txtFirstNameContact2.Text;
secondContact.LastName = txtlastNameContact2.Text;
secondContact.EmailAddress = txtEmailAddressContact2.Text;
secondContact.PhoneNumber = txtPhone1Contact2.Text + txtPhone2Contact2.Text + txtPhone3Contact2.Text;
if (!string.IsNullOrEmpty(rblContactTypeContact2.SelectedValue))
{
    secondContact.SecondaryContactTypeID = Convert.ToInt32(rblContactTypeContact2.SelectedValue);
}
secondContact.ContactPosition = 2;
secondContact.ProspectID = prospect.Id;

Sending the code to the repository to be saved with the code below (which it grabs the prospect.Id successfully):

if (prospect.Id != 0)
   {
    if (!string.IsNullOrEmpty(secondContact.FirstName) || !string.IsNullOrEmpty(secondContact.LastName) || !string.IsNullOrEmpty(secondContact.EmailAddress) || !string.IsNullOrEmpty(secondContact.PhoneNumber))
    {
        this.repository.SaveAltContact(prospect.Id, 2, secondContact);
    }
}

The repository trys to save the data:

public void SaveAltContact(int prospectID, int contactPosition, SecondaryContact contact)
{
    using (var context = new CoyleHomeBuyerEntities())
    {
        SecondaryContact currentAltContact = new Model.SecondaryContact();

        currentAltContact = (from sec in context.SecondaryContact
                             where sec.ContactPosition == contactPosition
                             where sec.ProspectID == prospectID
                             select sec).FirstOrDefault();

        if (currentAltContact == null)
        {
            context.AddToSecondaryContact(currentAltContact);
        }

        currentAltContact.FirstName = contact.FirstName;
        currentAltContact.LastName = contact.LastName;
        currentAltContact.EmailAddress = contact.EmailAddress;
        currentAltContact.PhoneNumber = contact.PhoneNumber;
        currentAltContact.SecondaryContactTypeID = contact.SecondaryContactTypeID;
        currentAltContact.ProspectID = prospectID;
        currentAltContact.ContactPosition = contactPosition;

        context.SaveChanges();
    }
}

It always fails after this line with a Null exception:

context.AddToSecondaryContact(currentAltContact);

I’m baffled, because I expect the query above to return a NULL value at this point. SecondaryContactID is set to be the primary key and to auto increment.

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: entity

Can someone point me in the right direction as to why this is failing when trying to add a new row to the database?

Answer 1

Actually I got it to work by simply declaring the currentAltContact variable at the top and instantiating a new object only if there was a null record

public void SaveAltContact(int prospectID, int contactPosition, SecondaryContact contact)
    {
        using (var context = new CoyleHomeBuyerEntities())
        {
                SecondaryContact currentAltContact;

            currentAltContact = (from sec in context.SecondaryContact
                                 where sec.ContactPosition == contactPosition
                                 where sec.ProspectID == prospectID
                                 select sec).FirstOrDefault();

            if (currentAltContact == null)
            {
                currentAltContact = new Model.SecondaryContact();
                context.AddToSecondaryContact(currentAltContact);
            }

            currentAltContact.FirstName = contact.FirstName;
            currentAltContact.LastName = contact.LastName;
            currentAltContact.EmailAddress = contact.EmailAddress;
            currentAltContact.PhoneNumber = contact.PhoneNumber;
            currentAltContact.SecondaryContactTypeID = contact.SecondaryContactTypeID;
            currentAltContact.ProspectID = prospectID;
            currentAltContact.ContactPosition = contactPosition;

            context.SaveChanges();
        }
    }