Learn to tidy up a bit (a). The function uses HttpHandler to realize the picture verification Code (b). The code is as follows 1. The handler file Validateimagehandler.ashx code is as follows 1 <% @ WebHandler Language = "C #" Class = "Validateimagehandler"%>
2
3 using System;
4 using System.Web;
5 using System.Web.SessionState;
6 using System.Drawing;
7 using System.Drawing.Imaging;
8 using System.Text;
9
Ten///<summary>
One///Validateimagehandler Build site authentication code feature
///</summary>
public class Validateimagehandler:ihttphandler, IRequiresSessionState
14 {
int intlength = 5; Length
String stridentify = "identify"; A random string stores key values so that they are stored in session
Validateimagehandler Public ()
18 {
19}
20
///<summary>
22///Build Verification Image Core code
///</summary>
///<param name= "HC" ></param>
public void ProcessRequest (HttpContext hc)
26 {
27//Set output stream picture format
HC. Response.ContentType = "Image/gif";
29
Bitmap B = new Bitmap (200, 60);
Graphics g = graphics.fromimage (b);
G.fillrectangle (New SolidBrush (Color.yellowgreen), 0, 0, 200, 60);
Font font = new Font (FONTFAMILY.GENERICSERIF, fontstyle.bold, GraphicsUnit.Pixel);
Random r = new Random ();
35
36//Legal random display character list
Panax Notoginseng String strletters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
StringBuilder s = new StringBuilder ();
39
40///draw randomly generated strings to the picture
A for (int i = 0; i < intlength i + +)
42 {
S.append (strletters.substring (r.next (0, strletters.length-1), 1));
g.DrawString (S[s.length-1]. ToString (), Font, New SolidBrush (Color.Blue), I *, R.next (0, 15));
45}
46
47//Generate interference lines
The pen pen = new Pen (new SolidBrush (Color.Blue), 2);
for (int i = 0; i < i + +)
50 {
G.drawline (pen, New Point (R.next (0, 199), R.next (0)), New Point (R.next (0, 199), R.next (0, 59));
52}
B.save (HC. Response.outputstream, imageformat.gif);
HC. Session[stridentify] = s.tostring (); First save in session, verify consistency with user input
HC. Response.End ();
56
57}
58
///<summary>
60///Indicates whether such instances can be shared by multiple requests (reuse can improve performance)
///</summary>
The public bool IsReusable
63 {
The Get
65 {
The return true;
67}
68}
69}
70
2. Front page Code 1 < Asp:login ID = "Login1" runat = "server" BackColor = "#EFF3FB" bordercolor = "#B5C7DE" Bord erpadding = "4" BorderStyle = "Solid" borderwidth = "1px" font-names = "Verdana" font-size = "0.8em" Fo Recolor = "#333333" onauthenticate = "Login1_authenticate" >
2 < TitleTextStyle BackColor = "#507CD1" font-bold = "True" font-size = "0.9em" ForeColor = "White"/>
3 < InstructionTextStyle font-italic = "True" ForeColor = "Black"/>
4 < TextboxStyle font-size = "0.8em"/>
5 < Loginbuttonstyle BackColor = "white" bordercolor = "#507CD1" BorderStyle = "Solid" Borderwid th = "1px"
6 font-names = "Verdana" font-size = "0.8em" ForeColor = "#284E98"/>
7
