/// <summary>
/// 判断用户是否登录成功
/// </summary>
/// <param name="PhoneOrMail">手机或邮箱</param>
/// <param name="pwd">密码</param>
/// <returns>登录信息</returns>
public static string stuLogin(string PhoneOrMail, string pwd)
{
return(StudentTable.hasUser(PhoneOrMail) == null? "该用户不存在":StudentTable.hasUser(PhoneOrMail).ToString() == pwd? "登录成功":"密码错误");
}