Updating error using (ling to sql)

Question

I have two tables, binded by foreign key CarrierID:

Carrier[CarrierID,CarrierName] 
CarrierID = 1, CarrierName = DHL
CarrierID = 2, CarrierName = Fedex
...
Vendo         


        

Answer 1

I expect it is this combination:

// somewhere
comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim();
...
// somewhere else
vendor.CarrierID = SelectedCarrierId;

One is using the object-oriented approach, one is using the id-based approach - however, if both are loaded and are incompatible, problems. I wonder if you should use:

vendor.Carrier = null;
vendor.CarrierID = SelectedCarrierId;

then there is exactly one definition of which carrier to use.

Alternatively, handle the carrier separately, for example, instead of:

comVendorCarrier.Text = vendor.Carrier.CarrierName.Trim();

use:

var carrier  = context.Carriers.Single(x => x.Id = vendor.CarrierId);
comVendorCarrier.Text = carrier.CarrierName.Trim();

which then never loads vendor.Carrier as an object.