Example.cs

public void Update()
{
	try
	{
		var user = db.Users.SingleOrDefault(x => x.UserId == userId);

		if (user == null)
		{
			throw new UserNotFoundException(userId);
		}

		// TODO: Validate the email address.
		user.EmailAddress = emailAddress;

		if (!string.IsNullOrEmpty(password))
		{
			user.Password = password;
		}

		user.StoreId = storeId;
		user.Role = role;

		db.SaveChanges();
	}
	catch (InvalidOperationException)
	{
		throw new MultipleUsersFoundException(userId);
	}
}