Codeusing 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.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
public partial class YanZhengMa : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
// 首先调用RndNum函数生成4位数字的验证码
string str_ValidateCode = RndNum(4);
// 然后把它保存在用于验证的Session里边
Session["imageCode"] = str_ValidateCode;
//调用CreateImage函数，把验证码绘制到图片中
CreateImage(str_ValidateCode);
}
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(new Char[] { ',' });
string VNum = "";
//int temp = -1;
Random rand = new Random();
for (int i = 1; i < VcodeNum + 1; i++)
{
int t = rand.Next(36);
VNum += VcArray[t];
}
return VNum;
}
//生成随机颜色
private Color GetRandomColor()
{
Random RandomNum_First = new Random((int)DateTime.Now.Ticks);
// 对于C#的随机数，没什么好说的
System.Threading.Thread.Sleep(RandomNum_First.Next(50));
Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);
// 为了在白色背景上显示，尽量生成深色
int int_Red = RandomNum_First.Next(256);
int int_Green = RandomNum_Sencond.Next(256);
int int_Blue = (int_Red + int_Green > 400) ? 0 : 400 - int_Red - int_Green;
int_Blue = (int_Blue > 255) ? 255 : int_Blue;
return Color.FromArgb(int_Red, int_Green, int_Blue);
}
public void CreateImage(string str_ValidateCode)
{
int int_ImageWidth = str_ValidateCode.Length * 13;
Random newRandom = new Random();
// 图高20px
Bitmap theBitmap = new Bitmap(int_ImageWidth, 20);
Graphics theGraphics = Graphics.FromImage(theBitmap);
// 白色背景
theGraphics.Clear(Color.White);
// 灰色边框
theGraphics.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, int_ImageWidth - 1, 19);
// 10pt的字体
Font theFont = new Font("Arial", 10);
for (int int_index = 0; int_index < str_ValidateCode.Length; int_index++)
{
string str_char = str_ValidateCode.Substring(int_index, 1);
Brush newBrush = new SolidBrush(GetRandomColor());
Point thePos = new Point(int_index * 13 + 1 + newRandom.Next(3), 1 + newRandom.Next(3));
theGraphics.DrawString(str_char, theFont, newBrush, thePos);
}
// 将生成的图片发回客户端
MemoryStream ms = new MemoryStream();
theBitmap.Save(ms, ImageFormat.Jpeg);
Response.ClearContent(); //需要输出图象信息 要修改HTTP头
Response.ContentType = "image/Png";
Response.BinaryWrite(ms.ToArray());
theGraphics.Dispose();
theBitmap.Dispose();
Response.End();
}
}
下面是使用代码
Code<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="CRM._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>无标题页</title>
<script type ="text/javascript">
function UpdateImage()
{
var n=Math.random();
document.getElementById("image").src="System/CheckCode.aspx?r="+n;
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<img id ="image" src ="System/CheckCode.aspx" />
<a href ="javascript:UpdateImage()">看不清啊</a>
</div>
</form>
</body>
</html>
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