loginform.cs

一个很好的宾馆管理系统 VC++和SQL做的

//文件名：LoginForm.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace MyHotel
{
    public partial class LoginForm : Form
    {
        public LoginForm()
        {
            InitializeComponent();
        }
        //记录用户登录次数
        private int MyTryCount = 0;
        private void 登录系统Button_Click(object sender, EventArgs e)
        {
                //从app.config文件中读取数据库连接字符串信息
                String MySQLConnectionString = global::MyHotel.Properties.Settings.Default.MyHotelConnectionString;
                string MySQL = "Select COUNT(*) From 操作用户 Where 用户名称=@用户名称 AND 用户密码=@用户密码";
                SqlConnection MyConnection = new SqlConnection(MySQLConnectionString);
                MyConnection.Open();
                SqlCommand MyCommand = new SqlCommand(MySQL, MyConnection);
                MyCommand.Parameters.Clear();
                SqlParameter MySqlNameParameter = new SqlParameter();
                MySqlNameParameter.ParameterName = "@用户名称";
                MySqlNameParameter.Value = this.用户名称TextBox.Text;
                MyCommand.Parameters.Add(MySqlNameParameter);
                SqlParameter MySqlPWParameter = new SqlParameter();
                MySqlPWParameter.ParameterName = "@用户密码";
                MySqlPWParameter.Value = this.用户密码TextBox.Text;
                MyCommand.Parameters.Add(MySqlPWParameter);
                int MyCount = (int)MyCommand.ExecuteScalar();
                if (MyCount == 1)
                {
                    this.Close();
                }
                else
                {
                          this.MyTryCount += 1;
                if (this.MyTryCount != 3)
                {
                    int MyDoCount = 3 - this.MyTryCount;
                    MessageBox.Show("用户密码或用户名称有错，还有" + MyDoCount + "次机会！", "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    this.用户密码TextBox.Text = "";
                    this.用户名称TextBox.Text = "";                    
                }
                else
                {
                    退出系统Button_Click(null, null);
                }
                }
                if (MyConnection.State == ConnectionState.Open)
                {
                    MyConnection.Close();
                }
        }
        private void 退出系统Button_Click(object sender, EventArgs e)
        {          
            MainForm MyDlg = (MainForm)this.Owner;
            MyDlg.Close();
        }
    }
}