练习登陆

 static void Main(string[] args)
        {
            //神奇的代码,该段代码在数据库连接中要加入 ，至于为什么我还不知道？
            string dataDir = AppDomain.CurrentDomain.BaseDirectory;
            if (dataDir.EndsWith(@"\bin\Debug\")
                || dataDir.EndsWith(@"\bin\Release\"))
            {
                dataDir = System.IO.Directory.GetParent(dataDir).Parent.Parent.FullName;
                AppDomain.CurrentDomain.SetData("DataDirectory", dataDir);
            }

            Console.WriteLine("请输入用户名：");
            string strUser = Console.ReadLine();
            Console.WriteLine("请输入密码：");
            string strPassWord = Console.ReadLine();

            //创建连接对象
            using (SqlConnection conn = new SqlConnection(@"Data Source=.\SQLEXPRESS;
AttachDbFileName=|DataDirectory|\Database1.mdf;
Integrated Security=true;
User Instance=True
"))
            {
                conn.Open();  //打开连接
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = "select * from TUser where FUser = '" + strUser + "'"; 
                    using (SqlDataReader dr = cmd.ExecuteReader()) //dr相当于记录集
                    {
                        //用户名存在
                        if (dr.Read())  //就是移到下一条记录，（现在是移到第一条，如果再read一次那就移到第二条）
                        {
                            string dbPassWord = dr.GetString(dr.GetOrdinal("FPassWord"));
                            if (dbPassWord == strPassWord)
                            {
                                Console.WriteLine("登陆成功");
                            }
                            else
                            {
                                Console.WriteLine("密码错误，登陆失败");
                            }
 
                        }
                        else //用户名不存在
                        {
                            Console.WriteLine("用户名不存在，登陆失败");
                        }
                    }
 
                }
            }
            Console.WriteLine("打开数据库连接成功");
            Console.ReadKey();

        }