asp.net一般处理程序（.ashx）动态生成验证码案例。
{使用一般处理程序动态生成验证码}
1.新建WebSite项目，添加一般处理程序命名为 yzm.ashx，添加如下代码：
public void ProcessRequest(HttpContext context)
{
//将context.Response.ContentType = "text/plain";修改为context.Response.ContentType =
"image/JPEG";
context.Response.ContentType =
"image/JPEG";
using
(System.Drawing.Bitmap bitmap
=
new System.Drawing.Bitmap(150,
50))
{
using
(System.Drawing.Graphics grapgics
=
System.Drawing.Graphics.FromImage(bitmap))
{
//测试示例
/*grapgics.DrawString("哈喽",
new System.Drawing.Font("宋体",
20),
System.Drawing.Brushes.Blue
, new System.Drawing.PointF(0,
0));
System.Drawing.Pen pen =
(System.Drawing.Pen)
System.Drawing.Pens.Red.Clone();
pen.Width =
3;
grapgics.DrawEllipse(pen, new System.Drawing.Rectangle(20, 20, 10,
10));
bitmap.Save(context.Response.OutputStream,
System.Drawing.Imaging.ImageFormat.Jpeg);*/
//生成随机数
Random random = new
Random();
int code =
random.Next();
string strCode = code.ToString();
//存session
HttpContext.Current.Session["code"] =
strCode;
grapgics.DrawString(strCode,
new System.Drawing.Font("宋体",
20),
System.Drawing.Brushes.Blue
, new System.Drawing.PointF(0,
0));
bitmap.Save(context.Response.OutputStream,
System.Drawing.Imaging.ImageFormat.Jpeg);
}
}
//本身就有的
context.Response.Write("Hello World");
}
2.新建webApplication。
在<div>中添加<img src="yzm.ashx"/>
添加TextBox 和Button,Button的单击事件如下
protected void Button1_Click(object sender, EventArgs
e)
{
string
stryzm =
Convert.ToString(Session["code"]);
if (stryzm==TextBox1.Text)
{
Response.Write("正确");
}
else
{
Response.Write("错误");
}
}
3.随后即可在WebApplication中进行测试。