asp.net生成图片验证码（数字）

来源：互联网发布：bt种子在线播放软件编辑：程序博客网时间：2024/06/03 22:48

前台用一个img来装

<img src="../png.aspx" id="img" onclick="f_refreshtype()" />

注意路径直接写你后台aspx文件

js实现点击刷新

   function f_refreshtype() {            var Image1 = document.getElementById("img");            if (Image1 != null) {                Image1.src = Image1.src + "?";            }        }

后台用一个aspx文件生成验证码图片（4位数字）

using System;using System.Collections.Generic;using System.Drawing;using System.Drawing.Drawing2D;using System.IO;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;namespace ChemGuanWeb{    public partial class png : System.Web.UI.Page    {        protected void Page_Load(object sender, EventArgs e)        {            if (!IsPostBack)            {                CreateCheckCodeImage(GenerateCheckCodes(4));            }        }        public void ShowAuthCode(Stream stream, out string code)        {            Random random = new Random();            code = random.Next(1000, 9999).ToString();            Bitmap bitmap = CreateAuthCode(code);            bitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Gif);        }        private string GenerateCheckCodes(int iCount)        {            int number;            string checkCode = String.Empty;            int iSeed = DateTime.Now.Millisecond;            System.Random random = new Random(iSeed);            for (int i = 0; i < iCount; i++)            {                number = random.Next(10);                checkCode += number.ToString();            }            Session["CheckCode"] = checkCode;            return checkCode;        }        private Bitmap CreateAuthCode(string str)        {            Font fn = new Font("宋体", 12);            Brush forecolor = Brushes.Black;            Brush bgcolor = Brushes.White;            PointF pf = new PointF(5, 5);            Bitmap bitmap = new Bitmap(100, 25);            Rectangle rec = new Rectangle(0, 0, 100, 25);            Graphics gh = Graphics.FromImage(bitmap);            gh.FillRectangle(bgcolor, rec);            gh.DrawString(str, fn, forecolor, pf);            return bitmap;        }        private void CreateCheckCodeImage(string checkCode)        {            if (checkCode == null || checkCode.Trim() == String.Empty)                return;            int iWordWidth = 15;            int iImageWidth = checkCode.Length * iWordWidth;            Bitmap image = new Bitmap(iImageWidth, 20);            Graphics g = Graphics.FromImage(image);            try            {                //生成随机生成器                 Random random = new Random();                //清空图片背景色                 g.Clear(Color.White);                //画图片的背景噪音点                for (int i = 0; i < 20; i++)                {                    int x1 = random.Next(image.Width);                    int x2 = random.Next(image.Width);                    int y1 = random.Next(image.Height);                    int y2 = random.Next(image.Height);                    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);                }                //画图片的背景噪音线                 for (int i = 0; i < 2; i++)                {                    int x1 = 0;                    int x2 = image.Width;                    int y1 = random.Next(image.Height);                    int y2 = random.Next(image.Height);                    if (i == 0)                    {                        g.DrawLine(new Pen(Color.Gray, 2), x1, y1, x2, y2);                    }                }                for (int i = 0; i < checkCode.Length; i++)                {                    string Code = checkCode[i].ToString();                    int xLeft = iWordWidth * (i);                    random = new Random(xLeft);                    int iSeed = DateTime.Now.Millisecond;                    int iValue = random.Next(iSeed) % 4;                    if (iValue == 0)                    {                        Font font = new Font("Arial", 13, (FontStyle.Bold | System.Drawing.FontStyle.Italic));                        Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);                        LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Blue, Color.Red, 1.5f, true);                        g.DrawString(Code, font, brush, xLeft, 2);                    }                    else if (iValue == 1)                    {                        Font font = new System.Drawing.Font("楷体", 13, (FontStyle.Bold));                        Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);                        LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Blue, Color.DarkRed, 1.3f, true);                        g.DrawString(Code, font, brush, xLeft, 2);                    }                    else if (iValue == 2)                    {                        Font font = new System.Drawing.Font("宋体", 13, (System.Drawing.FontStyle.Bold));                        Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);                        LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Green, Color.Blue, 1.2f, true);                        g.DrawString(Code, font, brush, xLeft, 2);                    }                    else if (iValue == 3)                    {                        Font font = new System.Drawing.Font("黑体", 13, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Bold));                        Rectangle rc = new Rectangle(xLeft, 0, iWordWidth, image.Height);                        LinearGradientBrush brush = new LinearGradientBrush(rc, Color.Blue, Color.Green, 1.8f, true);                        g.DrawString(Code, font, brush, xLeft, 2);                    }                }                //////画图片的前景噪音点                 //for (int i = 0; i < 8; i++)                //{                //    int x = random.Next(image.Width);                //    int y = random.Next(image.Height);                //    image.SetPixel(x, y, Color.FromArgb(random.Next()));                //}                //画图片的边框线                 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);                System.IO.MemoryStream ms = new System.IO.MemoryStream();                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);                Response.ClearContent();                Response.BinaryWrite(ms.ToArray());            }            finally            {                g.Dispose();                image.Dispose();            }        }    }}

生成的验证码被保存在session中，判断就直接获取到用户输入的验证码比较Session[“CheckCode”]里的值就ok了

阅读全文

0 0