C# 生成簡單驗證碼的代碼
2018-07-20 來源：open-open
C#生成簡單驗證碼的代碼
html頁面<!--
Document : ASP.NET用一般處理程序生成驗證碼
Created on : 2008-10-13 17：04
Author : 牛腩
-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<script type="text/javascript">
function change() {
var imgNode = document.getElementById("vimg");
imgNode.src = "WaterMark.ashx?t=" + (new Date()).valueOf(); // 這里加個時間的參數(shù)是為了防止瀏覽器緩存的問題
}
</script>
</head>
<body>
<img src="WaterMark.ashx" id="vimg" alt="" /><input type="button" value="換一張圖片" onclick="change()" />
</body>
</html>
C#代碼
//一般處理程序WaterMark.ashx的代碼
<%@ WebHandler Language="C#" Class="WaterMark" %>
using System;
using System.Web;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Web.SessionState;
public class WaterMark : IHttpHandler, IRequiresSessionState // 要使用session必須實現(xiàn)該接口,記得要導入System.Web.SessionState命名空間
{
public void ProcessRequest(HttpContext context)
{
string checkCode = GenCode(5); // 產(chǎn)生5位隨機字符
context.Session["Code"] = checkCode; //將字符串保存到Session中，以便需要時進行驗證
System.Drawing.Bitmap image = new System.Drawing.Bitmap(70, 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片背景色
g.Clear(Color.White);
// 畫圖片的背景噪音線
int i;
for (i = 0; i < 25; 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);
}
Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2F, true);
g.DrawString(checkCode, font, brush, 2, 2);
//畫圖片的前景噪音點
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);
context.Response.ClearContent();
context.Response.ContentType = "image/Gif";
context.Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
/// <summary>
/// 產(chǎn)生隨機字符串
/// </summary>
/// <param name="num">隨機出幾個字符</param>
/// <returns>隨機出的字符串</returns>
private string GenCode(int num)
{
string str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char[] chastr = str.ToCharArray();
// string[] source ={ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "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 code = "";
Random rd = new Random();
int i;
for (i = 0; i < num; i++)
{
//code += source[rd.Next(0, source.Length)];
code += str.Substring(rd.Next(0, str.Length), 1);
}
return code;
}
public bool IsReusable
{
get
{
return false;
}
}
}
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