conn.Open();
                

using

 (SqlCommand cmd = conn.CreateCommand())

                {
                    cmd.CommandText = 

"select * from T_Login"

;

                    

using

 (SqlDataReader reader = cmd.ExecuteReader())

                    {
                        

if

 (!reader.Read())

//在使用 Read()方法读取 SqlDataReader 类型的对象中的

数据的时候，不能在当前 conn 这个数据库连接字符串的 cmd 命令下修改数据库中的数据，
只能通过新建一个连接字符串来解决这个问题

                        {
                            MessageBox.Show(

"读取数据库数据出错！"

);

                        }
                        

else

                        {
                            

int

 ErrorTimes = reader.GetInt32(reader.GetOrdinal(

"ErrorTimes"

));

                            

if

 (ErrorTimes >= 

3

)

                            {
                                MessageBox.Show(

"错误次数过多，您的账户被锁定，程序将自动

退出"

);                                

                                Application.Exit();
                                

return

;

                            }
                            

string

 UserName = reader.GetString(reader.GetOrdinal(

"UserName"

));

                            

string

 PassWord = reader.GetString(reader.GetOrdinal(

"PassWord"

));

                            

if

 (UserName == strUserName && PassWord == strPassWord)

                            {
                                MessageBox.Show(

"登录成功"

);

                                ResetErrorTimes();
                            }
                            

else

                            {
                                MessageBox.Show(

"用户名或者密码错误"

);

                                IncErrorTimes();
                            }
                        }
                    }
                }
            }
        }
    }
}