ASP验证码代码

在ASP页面中生成图片验证码，需要用到System.Drawing命名空间下的很多类，首先我们需要新建一个CreateImage.aspx页面，在后台代码中定义用于生成验证码图片的方法，如下：

using System;

using System.Collections;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HTMLControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.XML.Linq;

using System.Drawing;

public partial class CreateImage : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

//产生4位验证码

string CheckCode = CreateCode(4);

//用于验证

Session["code"] = CheckCode;

CreateImages(CheckCode);

}

///

/// 产生验证码

///

///

///

public string CreateCode(int codeLength)

{

string so = "1,2,3,4,5,6,7,8,9,0,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O, P,Q,R,S,T,U,V,W,X,Y,Z";

string[] strArray = so.Split(',');

string code = "";

Random rand = new Random();

for (int i = 0; i < codeLength; i++)

{

//Random.Next(minValue,maxValue);

//一个大于或等于minValue 且小于maxValue 的32 位带符号整数，即：返回的值范围包括minValue 但不包括maxValue。如果

//minValue 等于maxValue，则返回minValue。

code += strArray[rand.Next(0, strArray.Length)];

}

return code;

}

///

/// 产生验证图片

///

///

public void CreateImages(string code)

{

//创建一个Bitmap新实例

Bitmap image = new Bitmap(60, 20);

Graphics g = Graphics.FromImage(image);

WebColorConverter ww = new WebColorConverter();

//清楚整个绘图面，并以制定颜色填充

g.Clear((Color)ww.ConvertFromString("#FAE264"));

Random rand = new Random();

//画图片的背景噪音线

for (int i = 0; i < 12; i++)

{

int x1 = rand.Next(image.Width);

int x2 = rand.Next(image.Height);

int y1 = rand.Next(image.Width);

int y2 = rand.Next(image.Height);

g.DrawLine(new Pen(Color.LightGray), x1, y1, x2, y2);

}

//新建字体

Font font = new Font("Arial", 15, FontStyle.Bold | FontStyle.Italic);

System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.Gray, 1.2f, true);

g.DrawString(code, font, brush, 0, 0);

//画图片的前景噪音

for (int i = 0; i < 10; i++)

{

int x = rand.Next(image.Width);

int y = rand.Next(image.Height);

image.SetPixel(x, y, Color.White);

}

//画图片的边框线

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);

Response.ClearContent();

Response.ContentType = "image/Gif";

Response.BinaryWrite(ms.ToArray());

g.Dispose();

image.Dispose();

}

#region Web 窗体设计器生成的代码

override protected void OnInit(EventArgs e)

{

//

// CODEGEN: 该调用是https://www.360docs.net/doc/263016151.html, Web 窗体设计器所必需的。

//

InitializeComponent();

base.OnInit(e);

}

///

/// 设计器支持所需的方法- 不要使用代码编辑器修改

/// 此方法的内容。

///

private void InitializeComponent()

{

this.Load += new System.EventHandler(this.Page_Load);

}

#endregion

}

以上是CreateImage.aspx文件的后台代码，完成上述方法后，在页面里调用方法，只需要添加，即可显示生成的验证码图片，每次刷新都会随机产生不同的验证码，如下：

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="CreateImage.aspx.cs" Inherits="CreateImage" %>

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Drawing;

public class Rand

{

public string rand;

Random ran = new Random(https://www.360docs.net/doc/263016151.html,lisecond);//加个随机数种子

public Rand()

{

for (int i = 0; i < 4; i++)

{

this.rand += ran.Next(0, 16).ToString("x1");

}

HttpContext.Current.Session.Add("code",this.rand);

}

}

public partial class image : System.Web.UI.Page

{

Random ran = new Random(https://www.360docs.net/doc/263016151.html,lisecond);//加个随机数种子public int x,y,p,q;

public int r, g, b;

protected void draw()

{

Rand R = new Rand();

Session["image"] = R.rand;

Bitmap image = new Bitmap(100, 50);//创建画布;

Graphics g = Graphics.FromImage(image);//创建画图对象;

g.Clear(Color.Black);

SolidBrush blackbrush = new SolidBrush(Color.White);

Font font = new Font("Verdana", 14);

for (int i = 0; i < 100; i++)

{

this.x = ran.Next(0, 100);

this.y = ran.Next(0, 50);

this.p = ran.Next(0, 100);

this.q = ran.Next(0, 50);

this.r = ran.Next(0, 256);

this.g = ran.Next(0, 256);

this.b = ran.Next(0, 256);

Pen pen = new Pen(Color.FromArgb(this.r, this.g, this.b));

g.DrawLine(pen, this.x, this.y, this.x, this.y + 1);

//g.DrawLine(pen, this.x, this.y, this.x + this.p, this.y + this.q);

}

g.DrawString(R.rand, font, blackbrush, 20, 10);

Response.ContentType = "image/jpeg";

image.Save(Response.OutputStream,

System.Drawing.Imaging.ImageFormat.Jpeg);//输出图片;

blackbrush.Dispose();//释放画笔;

g.Dispose();//释放绘图对象;

image.Dispose();//释放图形对象;

}

protected void Page_Load(object sender, EventArgs e) {

draw();

}

}