C# 图片验证码简单例子

一、简述

记--使用PictureBox绘制验证码。

例子：外链:https://wwm.lanzouq.com/b0cafckej密码:cxxn

二、效果

三、工程结构

四、源文件

Form1.cs文件

using System;
using System.Drawing;
using System.Windows.Forms;

namespace VerificationCode
{
    public partial class Form1 : Form
    {
        const int mRandomCharCount = 4;
        string mVerificationCode = "";
        public Form1()
        {
            InitializeComponent();
        }

        private void RefreshVerificationCode()
        {
            mVerificationCode = "";
            Random rdm = new Random();
            string[] fonts = { "微软雅黑", "宋体", "黑体", "隶书", "仿宋" };
            Color[] colors = { Color.Pink, Color.Blue, Color.Black, Color.Red, Color.Purple, Color.Green };
            const string randomStr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

            //随机生成4个字符
            for (int i = 0; i < mRandomCharCount; i++)
            {
                mVerificationCode += randomStr[rdm.Next(0, randomStr.Length)].ToString();
            }

            //4个字符按不同的字体颜色进行绘制
            Bitmap bmp = new Bitmap(pictureBoxVerificationCode.Width, pictureBoxVerificationCode.Height);
            Graphics g = Graphics.FromImage(bmp);
            for (int i = 0; i < mRandomCharCount; i++)
            {
                Point p = new Point(i * 27, 0);
                g.DrawString(mVerificationCode[i].ToString(), new Font(fonts[rdm.Next(0, fonts.Length)], 28, FontStyle.Bold), new SolidBrush(colors[rdm.Next(0, colors.Length)]), p);
            }

            //绘制17条线条
            for (int i = 0; i < 16; i++)
            {
                Point p1 = new Point(rdm.Next(0, bmp.Width), rdm.Next(0, bmp.Height));
                Point p2 = new Point(rdm.Next(0, bmp.Width), rdm.Next(0, bmp.Height));
                g.DrawLine(new Pen(Brushes.Green), p1, p2);
            }

            //绘制300个点
            for (int i = 0; i < 300; i++)
            {
                Point p = new Point(rdm.Next(0, bmp.Width), rdm.Next(0, bmp.Height));
                bmp.SetPixel(p.X, p.Y, Color.Black);
            }

            Console.WriteLine(mVerificationCode);
            //将图片镶嵌到PictureBox中
            pictureBoxVerificationCode.Image = bmp;
        }

        private void pictureBoxVerificationCode_Click(object sender, EventArgs e)
        {
            //刷新验证码
            RefreshVerificationCode();
        }

        private void buttonSure_Click(object sender, EventArgs e)
        {
            
            //if (textBoxVerificationCode.Text == mVerificationCode) //区分大小写
            if (textBoxVerificationCode.Text.Equals(mVerificationCode, StringComparison.OrdinalIgnoreCase)) //不s区分大小写
            {
                MessageBox.Show("验证码正确!", "提示");
            }
            else
            {
                MessageBox.Show("验证码错误!", "错误");
                RefreshVerificationCode();
                textBoxVerificationCode.Text = "";
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            RefreshVerificationCode();
        }
    }
}