Asp.NET验证码控件
在网上搜罗了一些验证码的方法，觉得这个算是最好的了，并且做了个小Demo，我有个习惯是把类放在类库里，做成DLL,下面是代码，和这个DLL的下载地址：
1.编译生成的DLL下载地址：下载ValidaterPicture.dll ，源文件如下：
ValidaterPictureClass.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Drawing;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
namespace ValidaterPicture
{
public class ValidaterPictureClass
{
public ValidaterPictureClass()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
//验证码的字符串
public static string ImageString;
/// <summary>
/// 绘制验证码图片方法
/// </summary>
public static void DrawImage()
{
ValidaterPictureClass img = new ValidaterPictureClass();
ValidaterPictureClass.ImageString = img.RndNum(6);
//HttpContext.Current.Session["CheckCode"] = ;
img.CreateImages(img.RndNum(6));
}
/// <summary>
/// 生成验证图片
/// </summary>
/// <param name="checkCode">验证字符</param>
private void CreateImages(string checkCode)
{
int iwidth = (int)(checkCode.Length * 13);
System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 23);
Graphics g = Graphics.FromImage(image);
g.Clear(Color.White);
//定义颜色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
//定义字体
string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };
Random rand = new Random();
//随机输出噪点
for (int i = 0; i < 50; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height);
g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);
}
//输出不同字体和颜色的验证码字符
for (int i = 0; i < checkCode.Length; i++)
{
int cindex = rand.Next(7);
int findex = rand.Next(5);
Font f = new System.Drawing.Font(font[findex], 10, System.Drawing.FontStyle.Bold);
Brush b = new System.Drawing.SolidBrush(c[cindex]);
int ii = 4;
if ((i + 1) % 2 == 0)
{
ii = 2;
}
g.DrawString(checkCode.Substring(i, 1), f, b, 3 + (i * 12), ii);
}
//画一个边框
g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);
//输出到浏览器
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
HttpContext.Current.Response.ClearContent();
//Response.ClearContent();
HttpContext.Current.Response.ContentType = "image/Jpeg";
HttpContext.Current.Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}
/// <summary>
/// 生成随机的字母
/// </summary>
/// <param name="VcodeNum">生成字母的个数</param>
/// <returns>string</returns>
private string RndNum(int VcodeNum)
{
string Vchar = "0,1,2,3,4,5,6,7,8,9,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[] VcArray = Vchar.Split(',');
string VNum = ""; //由于字符串很短，就不用StringBuilder了
int temp = -1; //记录上次随机数值，尽量避免生产几个一样的随机数
//采用一个简单的算法以保证生成随机数的不同
Random rand = new Random();
for (int i = 1; i < VcodeNum + 1; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
}
int t = rand.Next(VcArray.Length);
if (temp != -1 && temp == t)
{
return RndNum(VcodeNum);
}
temp = t;
VNum += VcArray[t];
}
return VNum;
}
}
}
2.新建项目，引入ValidaterPicture.dll类库。
3.创建PrintImage.aspx页，在页面的load中加入如下代码:
PrintImage.aspx.cs
using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using ValidaterPicture;
namespace WebDemo
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//创建验证码
ValidaterPictureClass.DrawImage();
//保存验证图片对应的验证字符串
Session ["str"] = ValidaterPictureClass.ImageString;
}
}
}
4.在需要使用的页面中加入ImageButton控件，注意图片地址为上面的PrintImage.aspx页地址：
<asp:ImageButton ID="ImageButton1" ImageUrl="~/PrintImage.aspx" runat="server" Height="21px" Width="85px" />
5.具体验证对照的使用方法，在使用页面的提交按钮中加入：
//获取该验证图片对应的字符串
string s = Session["str"].ToString();
if (TextBox1.Text.Trim().ToLower () == s.ToLower() )//tolower是大写转小写转换函数
{
Label1.Text = "验证正确";
}
