public async Task <User> AddUserAsync(User user)
{
if (user == null)
{
throw new ArgumentNullException("user cannot be null");
}
try
{
await this.modelContext.AddAsync(user);
await this.modelContext.SaveChangesAsync();
}
// duplicate email
catch (DbUpdateException exc) when((exc.InnerException as SqlException)?.Number == 2601)
{
this.modelContext.Remove(user);
throw UserException.DuplicateMailException(user.Credentials.Mail);
}
return(user);
}