private ResultWithEnum SaveCustomer(Customer customer)
{
try
{
using (var context = new MyContext())
{
context.Customers.Add(customer);
context.SaveChanges();
}
return(ResultWithEnum.Ok());
}
catch (DbUpdateException ex)
{
// Обрабатываем только те исключения, которые можем.
if (ex.Message == "Unable to open the DB connection")
{
return(ResultWithEnum.Fail(ErrorType.DatabaseIsOffline));
}
if (ex.Message.Contains("IX_Customer_Name"))
{
return(ResultWithEnum.Fail(ErrorType.CustomerAlreadyExists));
}
// Все остальные исключения - это аварийные случаи и ловятся только
// на самом верхнем уровне.
throw;
}
}
private ResultWithEnum SaveCustomer(Customer customer)
{
try
{
using (var context = new MyContext())
{
context.Customers.Add(customer);
context.SaveChanges();
}
return(ResultWithEnum.Ok());
}
catch (DbUpdateException ex)
{
if (ex.Message == "Unable to open the DB connection")
{
ResultWithEnum.Fail(ErrorType.DatabaseIsOffline);
}
if (ex.Message.Contains("IX_Customer_Name"))
{
return(ResultWithEnum.Fail(ErrorType.CustomerAlreadyExists));
}
throw;
}
}
private ResultWithEnum <Customer> GetCustomer(int id)
{
try
{
using (var context = new MyContext())
{
return(ResultWithEnum.Ok(context.Customers.Single(x => x.Id == id)));
}
}
catch (DbUpdateException ex)
{
if (ex.Message == "Unable to open the DB connection")
{
return(ResultWithEnum.Fail <Customer>(ErrorType.DatabaseIsOffline));
}
throw;
}
}
public void CreateCustomer(string name)
{
var customer = new Customer(name);
ResultWithEnum result = SaveCustomer(customer);
if (result.IsFailure)
{
switch (result.ErrorType)
{
case ErrorType.DatabaseIsOffline:
MessageBox.Show("Unable to connect to the database. Please try again later");
break;
case ErrorType.CustomerAlreadyExists:
MessageBox.Show("A customer with the name " + name + " already exists");
break;
default:
throw new ArgumentException();
}
}
}
