限制次数登录（ADO.Net）

Myth丶恋晨 2022-04-04 08:40 251阅读 0赞

**在原来数据库上加上次数统计列ErrorTimes**

**源码记录**

using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    using System.Data.SqlClient;
    namespace 登录厕所里hi
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
            private void  incErrorTimes()
            {
                using (SqlConnection conn = new
                  SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDBFilename=|DataDirectory|\MyDb1.mdf;Integrated Security=True;User Instance=True"))
                {
                    conn.Open();
    
                    using (SqlCommand updatecmd = conn.CreateCommand())
                    {
                        updatecmd.CommandText = "update T_Users Set ErrorTimes+=1 where UserName =@UserName";
    
                        updatecmd.Parameters.Add(new SqlParameter("UserName", txtUserName.Text));
                        updatecmd.ExecuteNonQuery();
                    }
                }
    
            }
            private void button1_Click(object sender, EventArgs e)
            {
                using (SqlConnection conn = new
                   SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDBFilename=|DataDirectory|\MyDb1.mdf;Integrated Security=True;User Instance=True"))
                {
                    conn.Open();
    
                    using (SqlCommand cmd = conn.CreateCommand())
                    {
                        cmd.CommandText = "select * from T_Users where UserName=@UserName";
                        cmd.Parameters.Add(new SqlParameter("UserName", txtUserName.Text));
                        using (SqlDataReader reader = cmd.ExecuteReader())
                        {
                            if (reader.Read())
                            {
    
                                int errorTimes  = reader.GetInt32(reader.GetOrdinal("ErrorTimes"));
                                if(errorTimes >3)
                                {
                                    MessageBox.Show("登录次数过多");
                                    return ;
                                }
                                string dbpassword =reader.GetString(reader.GetOrdinal("Password"));
                                if(dbpassword==txtPassword.Text)
                                {
    
                                  MessageBox.Show("登录成功");
    
                                }
                                else 
                                {
                                    incErrorTimes();
                                    MessageBox.Show("登录失败");
                                }
                            }
                            else
                            {
                                MessageBox.Show("用户名不存在");
                            }
                        }
                    }
                }
            }
        }
    }