C#实现系统登录

 1, 新建窗口frm_Login

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace WindowsFormsApp1
{public partial class Form_Login : Form{string Pwd = "";public Form_Login()//构造函数
        {InitializeComponent();}private void button1_Click(object sender, EventArgs e){//string name = this.textBox_name.Text;//string pwd = this.textBox_pwd.Text;
Form frm_login = new Form_Login();if (Pwd == this.textBox_pwd.Text){if (MessageBox.Show("登录成功!") == DialogResult.OK){//Form frm_socket = new Form_Socket();//frm_socket.ShowDialog();//打开该界面后,无法操作其他界面;//frm_socket.Show();//打开该界面后,可以操作其他界面;;
                }}else{MessageBox.Show("密码错误!");}}private void comboBox_name_SelectedIndexChanged(object sender, EventArgs e){if (comboBox_name.SelectedIndex==0)//操作员索引值=0
            {Pwd = "000";}else if (comboBox_name.SelectedIndex == 1)//维护员索引值=1
            {Pwd = "111";}else if (comboBox_name.SelectedIndex == 2)//管理员索引值=2
            {Pwd = "222";}}private void button_exit_Click(object sender, EventArgs e){this.Close();//关闭当前窗口//Application.Exit();//关闭应用程序;
        }private void Form_Login_Load(object sender, EventArgs e){comboBox_name.SelectedIndex = 0;//窗口加载时执行默认用户
        }}}