asp.net (C #) code for generating random verification codes _ Practical Tips

Commonly used to generate the verification Code program, the picture effect is as follows:

The source program is as follows:

Copy Code code as follows:

Using System;
Using System.IO;
Using System.Drawing;
Using System.Drawing.Imaging;
Using System.Text;
Using System.Collections;
Using System.Web;
Using System.Web.UI;
Using System.Web.UI.WebControls;
Using System.Web.UI.WebControls.WebParts;
Using System.Web.UI.HtmlControls;
/**////<summary>
///
* * asp.net (C #) Generate Verification code * *
///
File:GenerateCheckCode.aspx.cs
///
Author: Zhou Zhenxing (Zxjay drifting away)
///
E-mail:tda7264@163.com
///
Date:07-04-10
///
</summary>
public partial class GenerateCheckCode:System.Web.UI.Page
... {
protected void Page_Load (object sender, EventArgs e)
... {
String Chkcode = String. Empty;
A list of colors used to verify code, noise, and noise.
color[] color = ... {color.black, color.red, Color.Blue, Color.green, Color.orange, Color.brown, Color.brown, Color.DarkBlue};
Font list, for verification code
string[] Font = ... {"Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact"};
The character set of the verification code, removing some confusing characters
char[] character = ... {' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 8 ', ' 9 ', ' A ', ' B ', ' ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' J ', ' K ', ' L ', ' M ', ' N ', ' P ', ' R ', ' S ', ' T ', ' W ', ' X ', ' Y '};
Random rnd = new Random ();
To generate a validation code string
for (int i = 0; i < 4; i++)
... {
Chkcode + = Character[rnd. Next (character. Length)];
}
Bitmap bmp = new Bitmap (100, 40);
Graphics g = graphics.fromimage (BMP);
G.clear (Color.White);
Draw a noise line
for (int i = 0; i < i++)
... {
int x1 = rnd. Next (100);
int y1 = rnd. Next (40);
int x2 = rnd. Next (100);
int y2 = rnd. Next (40);
Color clr = color[rnd. Next (color. Length)];
G.drawline (new Pen (CLR), x1, y1, x2, y2);
}
Draw Verification Code string
for (int i = 0; i < chkcode.length; i++)
... {
String fnt = Font[rnd. Next (font. Length)];
Font ft = new Font (FNT, 18);
Color clr = color[rnd. Next (color. Length)];
g.DrawString (Chkcode[i]. ToString (), FT, new SolidBrush (CLR), (float) i * + 8, (float) 8);
}
Draw noise.
for (int i = 0; i < i++)
... {
int x = rnd. Next (BMP. Width);
int y = rnd. Next (BMP. Height);
Color clr = color[rnd. Next (color. Length)];
Bmp. SetPixel (x, Y, CLR);
}
Clears the page output cache, setting the page without caching
Response.Buffer = true;
Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds (0);
Response.Expires = 0;
Response.CacheControl = "No-cache";
Response.appendheader ("Pragma", "No-cache");
Writes the CAPTCHA picture to the memory stream and outputs it in "image/png" format
MemoryStream ms = new MemoryStream ();
Try
... {
Bmp. Save (MS, Imageformat.png);
Response.clearcontent ();
Response.ContentType = "Image/png";
Response.BinaryWrite (Ms. ToArray ());
}
Finally
... {
Explicit release of resources
Bmp. Dispose ();
G.dispose ();
}
}
}

Use the following methods:
Create a new file named Generatecheckcode.aspx, and copy the above code to the code file GenerateCheckCode.aspx.cs
Place the statement <asp:image id= "IMG1" runat= "Server" imageurl= "~/generatecheckcode.aspx"/> Where the authentication code is needed.