步步为营-41-登录失败3次,15分钟后才能登录

说明:登录失败3次,15分钟后才能登录

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

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

        private void btnLogin_Click(object sender, EventArgs e)
        {
            //操作数据库
            string id = txtUserName.Text.Trim();
            string pwd = txtPwd.Text.Trim();
            string strSQL = "select Id, Name, Pwd, Phone, Email, ErrorTimes, LastErrorTime,DATEDIFF(minute,LastErrorTime,getdate()) as ErrorMinute from UserInfo where Id =" + id;
            if (GetUserInfo(strSQL))
            {
                if (user.ErrorTimes>=3&&user.ErrorMinute<15 )
                {
                    MessageBox.Show("登录失败!用户被锁");
                    return;
                }
                if (pwd.Trim() == user.Pwd.Trim())
                {
                    //执行更新操作---ErrorTimes=0
                    strSQL = "Update UserInfo set ErrorTimes=0 where Id =" + id;
                    UpdateUserInfo(strSQL);
                    MessageBox.Show("登录成功");
                }
                else
                {
                    //执行更新操作---ErrorTime+1,LastErrorTime
                    user.ErrorTimes = user.ErrorTimes + 1;
                    strSQL = string.Format("Update UserInfo set ErrorTimes= {0},LastErrorTime='{1}' where Id ={2}", user.ErrorTimes,DateTime.Now, user.Id);
//                    strSQL = string.Format("Update UserInfo set ErrorTimes= {0},LastErrorTime={1}", user.ErrorTimes, DateTime.Now);
                    UpdateUserInfo(strSQL);
                    MessageBox.Show("登录失败!用户密码错误.错误次数"+user.ErrorTimes);
                }
            }
            else
            {
                MessageBox.Show("登录失败!用户不存在");
            }
        }

        public UserInfo user = new UserInfo();
        public bool GetUserInfo(string  strSQL)
        {
            //创建连接字符串
            string connstr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            //连接数据库
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                conn.Open();
                using (SqlCommand cmd = new SqlCommand(strSQL,conn))
                {
                    using (SqlDataReader reader = cmd.ExecuteReader())
                    {
                        if (reader.Read())
                        {
                            user.Id = Convert.ToInt32(reader["Id"].ToString());
                            user.Pwd = reader["Pwd"].ToString();
                            //数据库中设置不能为空,默认值为0,不然转换会出错
                            user.ErrorTimes =Convert.ToInt32(reader["ErrorTimes"].ToString());
                            user.ErrorMinute =Convert.ToInt32(reader["ErrorMinute"].ToString());
                            return true;
                        }
                    }
                       
                    }
                }
            return false;
            }

        public bool UpdateUserInfo(string strSQL)
        {
            //创建连接字符串
            string connstr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            //连接数据库
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                conn.Open();
                using (SqlCommand cmd = new SqlCommand(strSQL, conn))
                {
                    if (cmd.ExecuteNonQuery()>0)
                    {
                        return true;
                    }
                }
            }
            return false;
        }
            
        }
    }

注:参数格式化

cmd.CommandText=@"select count(*)  from UserInfo where UserName = @UserName and UserPwd = @UserPwd";

cmd.Parameters.Add("@UserName",txtUserName.Text);

cmd.Parameters.AddWithValue("@demo",0);