通过ashx创建image图片验证

最新推荐文章于 2024-12-30 11:23:31 发布

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最新推荐文章于 2024-12-30 11:23:31 发布

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本文链接：https://blog.youkuaiyun.com/ligenyingsr/article/details/11799731

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这篇博客介绍了如何通过ashx创建image图片验证，包括后台生成随机字符串和创建带噪点的图片，以及前端如何引用并避免缓存。

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ashx 代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Drawing;
using System.Web.UI.WebControls;
using System.IO;
using System.Web.SessionState;

namespace WirteToXmlSulotion.Agent
{
    /// <summary>
    /// Ag_CreateImage 的摘要说明
    /// </summary>
    public class Ag_CreateImage : IHttpHandler, IRequiresSessionState
    {

        public void ProcessRequest(HttpContext context)
        {
            string checkCode = CreateCode(4);

            //用于验证
            context.Session["CheckCode"] = checkCode;
            MemoryStream ms= CreateImages(checkCode);
            context.Response.ClearContent();
            context.Response.ContentType = "image/Gif";
            context.Response.BinaryWrite(ms.ToArray());
        }

        public string CreateCode(int codeLength)
        {

            string so = "1,2,3,4,5,6,7,8,9,0,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
            string[] strArr = so.Split(',');
            string code = "";
            Random rand = new Random();
            for (int i = 0; i < codeLength; i++)
            {
                code += strArr[rand.Next(0, strArr.Length)];
            }
            return code;
        }

        /*产生验证图片*/
        public MemoryStream CreateImages(string code)
        {

            Bitmap image = new Bitmap(60, 30);
            Graphics g = Graphics.FromImage(image);
            WebColorConverter ww = new WebColorConverter();
            g.Clear((Color)ww.ConvertFromString("#FAE264"));

            Random random = new Random();

            //画图片的背景噪音线
            for (int i = 0; i < 10; 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.LightGray), x1, y1, x2, y2);//Color.LightGray
            }
            Font font = new Font("Arial", 15, FontStyle.Bold | FontStyle.Italic);
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(
            new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.Gray, 1.2f, true);
            g.DrawString(code, font, brush, 0, 0);

            //画图片的前景噪音点
            for (int i = 0; i < 10; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);
                image.SetPixel(x, y, Color.White);
            }

            //画图片的边框线
            g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

            MemoryStream ms = new MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            g.Dispose();
            image.Dispose();
            return ms;
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}