/// <summary>
 /// 查询用户是否存在
 /// username  \  phone  \ email 返回为true时,验证成功
 /// </summary>
 /// <param name="username"></param>
 /// <returns></returns>
 private bool ExistUser(string username)
 {
     try
     {
         using (var db = new SQLServerDataContext())
         {
             f_user user = null;
             user = (from x in db.f_user
                     where x.username == username || x.phone == username || x.email == username
                     select x).SingleOrDefault() ?? null;
             if (user == null)
             {
                 return(false);
             }
             else
             {
                 return(true);
             }
         }
     }
     catch (Exception ex)
     {
         LogHelper.Log.Error("用户不存在 " + ex.Message);
         return(false);
     }
 }
 /// <summary>
 /// 用户注册
 /// </summary>
 /// <param name="username"></param>
 /// <param name="pwd"></param>
 /// <param name="phone"></param>
 /// <param name="email"></param>
 /// <returns></returns>
 private bool Register(string username, string pwd, string phone, string email)
 {
     try
     {
         using (var db = new SQLServerDataContext())
         {
             f_user option = null;
             option = (from x in db.f_user
                       where x.username == username || x.phone == phone || x.email == email
                       select x).SingleOrDefault() ?? null;
             if (null != option)
             {
                 option.username         = username;
                 option.password         = pwd;
                 option.email            = email;
                 option.phone            = phone;
                 option.create_date      = DateTime.Now;
                 option.last_update_date = DateTime.Now;
             }
             else
             {
                 option = new f_user()
                 {
                     username         = username,
                     password         = pwd,
                     phone            = phone,
                     email            = email,
                     create_date      = DateTime.Now,
                     last_update_date = DateTime.Now
                 };
                 db.f_user.InsertOnSubmit(option);
             }
             db.SubmitChanges();
             return(true);
         }
     }
     catch (Exception ex)
     {
         LogHelper.Log.Error("注册失败..." + ex.Message);
         return(false);
     }
 }