private static void UpdateRecord(int carId)
{
using (var context = new AutoLotDbContext())
{
var carToUpdate = context.Cars.Find(carId);
if (carToUpdate != null)
{
Console.WriteLine(context.Entry(carToUpdate).State);
carToUpdate.Color = "Blue";
Console.WriteLine(context.Entry(carToUpdate).State);
context.SaveChanges();
}
}
}
private static void ExplicitLoading()
{
using (var context = new AutoLotDbContext())
{
context.Configuration.LazyLoadingEnabled = false; //to guarantee nothing more loaded
foreach (var car in context.Cars)
{
context.Entry(car).Collection(x => x.Orders).Load();
foreach (var order in car.Orders)
{
Console.WriteLine(order.OrderId);
}
}
foreach (var order in context.Orders)
{
context.Entry(order).Reference(x => x.Car).Load();
}
}
}
private static void RemoveRecord(int carId)
{
using (var context = new AutoLotDbContext())
{
var carToDelete = context.Cars.Find(carId); //first load entity and then delete it
if (carToDelete != null)
{
context.Cars.Remove(carToDelete);
}
Console.WriteLine(context.Entry(carToDelete).State); //Deleted
context.SaveChanges();
}
}
private static void RemoveRecordUsingEntityState(int carId)
{
using (var context = new AutoLotDbContext())
{
var carToDelete = new Car{ CarId = carId };
//var car = context.Cars.Find(carId); //to fail
context.Entry(carToDelete).State = EntityState.Deleted; //will fail if item with the same key already tracked
try
{
context.SaveChanges();
}
catch (DbUpdateConcurrencyException ex) //will fail if no entity with such Id
{
Console.WriteLine(ex);
}
}
}
public int Save(T entity)
{
_ctx.Entry(entity).State = EntityState.Modified;
return(SaveChanges());
}
