C# Web 数字+字母验证码

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Drawing;

using System.IO;

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

{

protected void Page_Load(object sender, EventArgs e)

{

string checkCode = CreateCode(4);

Session["CheckCode"] = checkCode;

CreateImage(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[] strArr = so.Split(',');

string code = "";

Random rand = new Random();

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

{

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

}

return code;

}

/*产生验证图片*/

public void CreateImage(string code)

{

Bitmap image = new Bitmap(60, 20);

Graphics g = Graphics.FromImage(image);

WebColorConverter ww = new WebColorConverter();

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

Random random = new Random();

//画图片的背景噪音线

for (int i = 0; i < 12; 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.LightGray), x1, y1, x2, y2);

}

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);

//画图片的前景噪音点

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

{

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

int y = random.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();

}

}