先建一張生成驗證碼的網頁CheckCode.aspx:
CheckCode.aspx.cs代碼如下
添加引用:
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
public partial class Default2 : System.Web.UI.Page
{
private Bitmap validateimage;
private Graphics g;
protected void Page_Load(object sender, EventArgs e)
{
Response.BufferOutput = true; //特別注意
Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));//特別注意
Response.Cache.SetCacheability(HttpCacheability.NoCache);//特別注意
Response.AppendHeader(" Pragma", "No-Cache"); //特別注意
string VNum = MakeValidateCode();
Session["VNum"] = VNum;//取得驗證碼，以便後來驗證
ValidateCode(VNum);
}
public void ValidateCode(string VNum)
{
validateimage = new Bitmap(60, 20, PixelFormat.Format24bppRgb);
g = Graphics.FromImage(validateimage);
g.FillRectangle(new LinearGradientBrush(new Point(0, 0), new Point(110, 20), Color.FromArgb(240, 255, 255, 255), Color.FromArgb(240, 255, 255, 255)), 0, 0, 200, 200); //矩形框
g.DrawString(VNum, new Font("arial", 11), new SolidBrush(Color.Red), new PointF(6, 0));//字體/顏色
g.Save();
MemoryStream ms = new MemoryStream();
validateimage.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.C;
Response.BinaryWrite(ms.ToArray());
Response.End();
}
string MakeValidateCode()
{
char[] s = new char[] { '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','A','B', 'C','D','E','F','G','H','I','J','K','L','M','N','P','Q','I','S','T','U','V','W','X','Y','Z'};//枚舉數組
string num = "";
Random r = new Random();
for (int i = 0; i < 5; i++)
{
num += s[r.Next(0, s.Length)].ToString();
}
return num;
}
}
然後是顯示驗證碼的頁面 的html中加入<img src="Default2.aspx" id="yzm" alt="點擊刷新" />
在</head>之前一行加入javascript腳本語言如下(當然寫在JS文件裏面更好):
<script type="text/javascript">
function reloadcode(){
document.getElementById("yzm").src ="CheckCode.aspx";
}
</script>
本文來自CSDN博客，轉載請標明出處：http://blog.csdn.net/fanfengchimo/archive/2007/07/25/1707308.aspx
