验证码

最新推荐文章于 2025-02-26 20:36:13 发布

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#random #string #class #graph #c #c#

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本文介绍了一种使用C#生成验证码的方法，包括创建随机字母组合及背景干扰线，并将其保存为GIF格式图片的过程。

<%@ WebHandler Language="C#" Class="MyHandler" %>
using System;
using System.Web;
using System.Web.SessionState;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;

public class MyHandler : IHttpHandler, IRequiresSessionState {
    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "image/gif";
        Bitmap basemap = new Bitmap(150, 45);
        Graphics graph = Graphics.FromImage(basemap);
        graph.FillRectangle(new SolidBrush(Color.White), 0, 0, 150, 45);
        Font font = new Font(FontFamily.GenericSerif, 38, FontStyle.Bold, GraphicsUnit.Pixel);
        Random r = new Random();
        string letters = "ABCDEFGHIJKLMNPQRSTUVWXYZ123456789abcdefghijklmnpqrstuvwxyz";
        string letter = string.Empty;
        StringBuilder sb = new StringBuilder();
        Color c1 = Color.FromArgb(17, 129, 190);
        Color c2 = Color.FromArgb(115, 17, 190);
        Color c3 = Color.FromArgb(3, 106, 76);
        Color c4 = Color.FromArgb(98, 80, 15);
        Color c5 = Color.FromArgb(94, 8, 102);
        Color[] color = new Color[] { c1, c2, c3, c4, c5 };
        for (int x = 0; x < 5; x++)
        {
            letter = letters.Substring(r.Next(0, letters.Length - 1), 1);
            sb.Append(letter);
            graph.DrawString(letter, font, new SolidBrush(color[r.Next(0, 4)]), x * 26, r.Next(0, 3));
        }
        for (int x = 0; x < 3; x++)
        {
            Pen linePen = new Pen(new SolidBrush(color[r.Next(0, 4)]), 2);
            graph.DrawLine(linePen, new Point(r.Next(0, 149), r.Next(0, 44)), new Point(r.Next(0, 149), r.Next(0, 44)));
        }
        basemap.Save(context.Response.OutputStream, ImageFormat.Gif);
        graph.Dispose();
        basemap.Dispose();
        context.Session["CheckCode"] = sb.ToString();
        context.Response.End();
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}