name = 'alex'   #正确的用户名
passwd = '123456'  #正确的密码
lock_usr = []   #锁定账号列表

for i in range(0,3):
 usr_name = input("用户名：")
 usr_passwd = input("密码：")
 if usr_name == name and usr_passwd == passwd:
  print("玩命加载中...")
  break
 elif name != usr_name or passwd != usr_passwd:
  if i  2:
   print("用户名密码错误，请重新输入！")
  else:
   lock_usr.append(usr_name)     #将输入错误三次的的账号添加到锁定列表中
   print("对不起！机会只有三次，您的账号密码被锁定")
 elif usr_name in lock_usr:
  print("该账号已锁定，请解锁后登陆")

#region 密码输入三次错误后锁定用户功能
  #region 增加错误次数的方法
  ///summary>
  ///增加错误次数的方法
  ////summary>
  private void IncErrorTime()
  {
   string ConnStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
   using (SqlConnection conn = new SqlConnection(ConnStr))
   {
    using (SqlCommand updateCmd = conn.CreateCommand())
    {
     updateCmd.CommandText = "update T_Admin set errortime=errortime+1 whereUsername=@username";
     updateCmd.Parameters.Add(new SqlParameter("username", cmbuserName.Text));
     conn.Open();
     updateCmd.ExecuteNonQuery();
    }
   }
  } 
  #endregion
  #region 错误次数清0
  ///summary>
  ///错误次数清0
  ////summary>
  private void NotErrorTime()
  {
   string ConnStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
   using (SqlConnection conn = new SqlConnection(ConnStr))
   {
    using (SqlCommand updateCmd = conn.CreateCommand())
    {
     updateCmd.CommandText = "update T_Admin set errortime=0 whereUsername=@username";
     updateCmd.Parameters.Add(new SqlParameter("username", cmbuserName.Text));
     conn.Open();
     updateCmd.ExecuteNonQuery();
    }
   }
  } 
  #endregion
  #region 密码错误3次,记录当前时间加30分钟
  ///summary>
  ///密码错误3次,记录当前时间加30分钟
  ////summary>
  private void IncLoginTime()
  {
   string ConnStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
   using (SqlConnection conn = new SqlConnection(ConnStr))
   {
    using (SqlCommand updateCmd = conn.CreateCommand())
    {
     updateCmd.CommandText = "update T_Admin set logintime=@logintime whereUsername=@username";
     DateTime logintime = DateTime.Now.AddMinutes(30);
     updateCmd.Parameters.Add(new SqlParameter("username", cmbuserName.Text));
     updateCmd.Parameters.Add(new SqlParameter("logintime", logintime.ToString()));
     conn.Open();
     updateCmd.ExecuteNonQuery();
    }
   }
  } 
  #endregion
  #region 按钮事件判断用户登录3次失效后锁定用户30分钟
  private void BtnClike()
  {
   string username = cmbuserName.Text;
   string password = txtPwd.Text;
   string ConnStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
   using (SqlConnection conn = new SqlConnection(ConnStr))
   {
    using (SqlCommand cmd = conn.CreateCommand())
    {
     cmd.CommandText = "select * from T_Admin whereusername=@username";
     cmd.Parameters.Add(new SqlParameter("username", username));
     conn.Open();
     using (SqlDataReader reader = cmd.ExecuteReader())
     {
      if (reader.Read())
      {
       //用户存在
       string dbpassword = reader.GetString(reader.GetOrdinal("password"));
       DateTime logintime = reader.GetDateTime(reader.GetOrdinal("logintime"));
       //判断当前时间是是服务器允许登录时间
       if (logintime > DateTime.Now)
       {
        MessageBox.Show("一定时间内禁止登录");
        return;
       }
       //如果密码正确
       if (dbpassword == txtPwd.Text)
       {
        NotErrorTime();
        MessageBox.Show("登录成功!");
       }
       //如果密码错误
       else
       {
        int errortime = reader.GetInt32(reader.GetOrdinal("errortime"));
        if (errortime >= 2)
        {
         MessageBox.Show("密码错误次数太多!");
         IncLoginTime();
         NotErrorTime();
         return;
        }
        MessageBox.Show("密码错误!");
        IncErrorTime();//密码错误,次数加1
       }
      }
      else//用户名不存在
      {
       MessageBox.Show("用户名不存在!");
       return;
      }
     }
    }
   }
  }
  #endregion
  #endregion