form1.cs

在登录时

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace 登录加密验证
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string a = textBox1.Text + "##" + Base64.Encrypt(textBox2.Text);
            FileStream fs = new FileStream("myfile.txt", FileMode.Open, FileAccess.Read);
            StreamReader sr = new StreamReader(fs);
            string str;
            label3.Text = "";
            do
            {
                 str = sr.ReadLine();
                if (a == str)
                {

                    Form2 f2 = new Form2();
                    f2.Show();
                    break;
                }
                else
                {
                    label3.Text = "用户名或密码错误";
                }

            }
            while (str != null);
            sr.Close();
            fs.Close();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            string a = textBox1.Text + "##" + Base64.Encrypt(textBox2.Text);
            FileStream fs = new FileStream("myfile.txt", FileMode.Append, FileAccess.Write);
            StreamWriter w = new StreamWriter(fs);
            w.WriteLine(a);
            w.Close();
            fs.Close();
        }
    }
}