Net学习日记_ADO.Net_2_练习（登录逻辑）

要求：

页面：

数据库设定

主程序

using System;
using System.Data.SqlClient;
using System.Windows.Forms;

namespace Test01
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void BtOK_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection("server=PC201609230944\SQL2005;database=HeiMaBlog;user=sa;pwd=123456");
            SqlCommand cmd = new SqlCommand("select *,datediff(minute,LastErrTime,GETDATE()) from UserInfo where UserName=@UserName", conn);
            cmd.Parameters.Add(new SqlParameter("@UserName", TxName.Text.Trim()));
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();

            if (dr.HasRows)
            {
                dr.Read();////不管dr取到多少条数据，只取出前面第一行(调用一次read，就会读取一行，也只读取一行)
                if (dr.GetInt32(5) < 15)
                {
                    MessageBox.Show("时间未到，请稍后重试！！");
                    return;
                }

                if (dr[2].ToString() == TxPwd.Text.Trim())
                {
                    MessageBox.Show("登录成功！！");
                    UserInfo.ReSetErrTimes(dr.GetInt32(0));//登录成功后，就重置错误时间
                }
                else
                {
                    //如果密码不正确！！
                    MessageBox.Show("登录失败，密码错误");
                    UserInfo.UpDateErrTimes(dr.GetInt32(0));
                    // 错误三次就更新错误时间
                    if (dr.GetInt32(3) + 1 == 3)
                    {
                        UserInfo.UpDateLastErrTime(dr.GetInt32(0));
                        UserInfo.ReSetErrTimes(dr.GetInt32(0));
                    }
                }
            }
            else
            {
                MessageBox.Show("该用户不存在！！！");
            }
        }
    }
}

辅助

using System.Data.SqlClient;

namespace Test01
{
    class UserInfo
    {
        /// <summary>
        /// 更新错误时间！！
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static int UpDateErrTimes(int id)
        {
            using (SqlConnection conn = new SqlConnection("server=PC201609230944\SQL2005;database=HeiMaBlog;user=sa;pwd=123456"))
            {
                using (SqlCommand cmd = new SqlCommand("update UserInfo set ErrTimes=ErrTimes+1 where id=" + id, conn))
                {
                    conn.Open();
                    return cmd.ExecuteNonQuery();
                }
            }
        }

        /// <summary>
        /// 重置错误时间
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static int ReSetErrTimes(int id)
        {
            using (SqlConnection conn = new SqlConnection("server=PC201609230944\SQL2005;database=HeiMaBlog;user=sa;pwd=123456"))
            {
                using (SqlCommand cmd = new SqlCommand("update UserInfo set ErrTimes=0 where id=" + id, conn))
                {
                    conn.Open();
                    return cmd.ExecuteNonQuery();
                }
            }
        }

        /// <summary>
        /// 更新3次错误的输入时间
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public static int UpDateLastErrTime(int id)
        {
            using (SqlConnection conn = new SqlConnection("server=PC201609230944\SQL2005;database=HeiMaBlog;user=sa;pwd=123456"))
            {
                using (SqlCommand cmd = new SqlCommand("update UserInfo set LastErrTime = getDate() where id= " + id, conn))
                {
                    conn.Open();
                    return cmd.ExecuteNonQuery();
                }

            }

        }

    }
}

 注意:SqlDataReader的Read将数据读取出来到本地而已，对读取出来的本地数据进行整改对数据库没有啥作用。