. NET picture Verification code, final completion version __.net

Yesterday I tried the example in the book, but under. NET 2005 there was always an error, prompted that the method rewrite could not be found, and then tried another method.

Set up a class, used to draw random characters, and then build a.aspx, in the pageload call this class, and then the login page of the img src attribute, set to this a.aspx, run it.

The code for the class.

Using System;
Using System.Collections.Generic;
Using System.Text;
Using System.Drawing;
Using System.Web;
Using System.Web.SessionState;

Namespace Webhelper.picture
{
/**/
<summary>
Chinese Picture Verification Code
</summary>
public class Valids:System.Web.UI.Page
{
/**/
<summary>
Generate a random text picture, saved in session["Validcode"]
</summary>
<param name= "Count" > The number of words in the picture </param>
<returns> generated Text </returns>
public static void CreateImage (int count)
{
String Validcode = Gencode (count);
Createcheckcodeimage (Validcode);
httpcontext.current.session["Validcode"] = Validcode;
}

/**/
<summary>
Generate Random strings
</summary>
<param name= "num" > random out a few characters </param>
<returns> random out of the string </returns>
private static string gencode (int num)
{
String validatecode = "";

Random Number Object
Random Random = new Random ();

for (int i = 0; i < num; i++)
{
26:a-Z
int n = random. Next (26);

Convert numbers to uppercase letters
Validatecode + = (char) (n + 65);
}

return validatecode;

}

/**/
<summary>
Generate picture (Increase background noise line, foreground noise point)
</summary>
<param name= "Checkcode" > Random out String </param>
private static void Createcheckcodeimage (String checkcode)
{
if (checkcode.trim () = = "" | | Checkcode = null)
Return
System.Drawing.Bitmap image = new System.Drawing.Bitmap ((int) (CHECKCODE.LENGTH * 21.5), 22);
Graphics g = graphics.fromimage (image);
Try
{
Generate a random generator
Random Random = new Random ();

Empty picture background color
G.clear (Color.White);

Background noise line for painting pictures
int i;
for (i = 0; i < 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", (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);

Picture of the foreground noise point
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);
HttpContext.Current.Response.ClearContent ();
HttpContext.Current.Response.ContentType = "Image/gif";
HttpContext.Current.Response.BinaryWrite (Ms. ToArray ());
}
Catch
{
G.dispose ();
Image. Dispose ();
}
}
}
}

Join in the pageload of a.aspx

WebHelper.Picture.Valids.CreateImage (4);