/// <summary> 检查 <paramref name="email"/> 是否可以作为新账号的 <see cref="IAccount.Email"/>. </summary>
/// <param name="accountManager">The <see cref="IAccountManager"/></param>
/// <param name="email">The email address to be checked.</param>
/// <param name="allowReuse">If an email address can be registered by multiple users.</param>
public static EmailAvailableResult Check(IAccountManager accountManager, String email, bool allowReuse)
{
if (accountManager == null) throw new ArgumentNullException("accountManager");
if (String.IsNullOrEmpty(email)) throw new ArgumentException("email is null or empty.", "email");
if (!allowReuse)
{
var users = accountManager.FetchAccountsByEmail(email);
if (users.Any())
{
String errorMessage = String.Format("Email [{0}] is already registered.", email);
return new EmailAvailableResult(false, errorMessage, users);
}
}
return new EmailAvailableResult(true, null, null);
}