*******************************************处理程序（CheckCode.ashx）***************************/ public class CheckCode : IHttpHandler,System.Web.SessionState.IRequiresSessionState //注意处理程序应用session需要的System.Web.SessionState.IRequiresSessionState接口 {
public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "image/jpeg";
using (System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(80, 30)) {
using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap)) {
g.DrawString("你好吗",new System.Drawing.Font("宋体",20), System.Drawing.Brushes.Green ,new System.Drawing.PointF(0,0) );
System.Drawing.Pen pen= (System.Drawing.Pen)System.Drawing.Pens.Red.Clone();
pen.Width=5;
g.DrawEllipse(pen,new System.Drawing.Rectangle(10,10,10,10)); bitmap.Save(context.Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);//上面是自己手写的图片
Random r = new Random();
int random=r.Next(0,9999);
string code = random.ToString();
HttpContext.Current.Session["code"] = code;//数字验证码
byte[] bytes = new byte[100];
Random randObj = new Random();
int code;
for (int i = 0; i < 4; i++) {
code = randObj.Next(44, 122); bytes[i] = Convert.ToByte(code);
}
System.Text.ASCIIEncoding ascii = new System.Text.ASCIIEncoding();
string validateCode = ascii.GetString(bytes, 0, 4);
string strcode= validateCode.ToString();//根据ASCII码随机获取的验证码
g.DrawString(code,new System.Drawing.Font("宋体",20),System.Drawing.Brushes.Green,new System.Drawing.PointF(0,0)); bitmap.Save(context.Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);
}
} }
/*******************************************页面对验证码的应用***************************/
<form id="form1" runat="server"> <div> <img src="CheckCode.ashx" onclick="this.src='CheckCode.ashx?date='+new Date()" />//点击验证码一次回传给ashx一次，刷新一下验证码（注意参数为时间不会一样的） <br />
</div>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <asp:Button ID="Button1" runat="server" Text="确定" onclick="Button1_Click" />
</form>
protected void Button1_Click(object sender, EventArgs e) {
if (TextBox1.Text == Session["code"].ToString()) { Response.Write("验证通过！"); } else { Response.Write("验证失败！");
}
}