asp.net 验证码生成和刷新及验证

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Text;
/**///// <sumMary>
/// 页面验证码程序
/// 使用：在页面中加入HTML代码 <img src="VerifyCode.aspx">
/// </sumMary>
public partial class VerifyCode : System.Web.UI.Page
...{
static String[] FontItems = new String[] ...{ "Arial",
"Helvetica",
"Geneva",
"sans-serif",
"Verdana"
};
static Brush[] BrushItems = new Brush[] ...{ Brushes.OliveDrab,
Brushes.ForestGreen,
Brushes.DarkCyan,
Brushes.LightSlateGray,
Brushes.RoyalBlue,
Brushes.SlateBlue,
Brushes.DarkViolet,
Brushes.MediumVioletRed,
Brushes.IndianRed,
Brushes.Firebrick,
Brushes.Chocolate,
Brushes.Peru,
Brushes.Goldenrod
};
static String[] BrushName = new String[] ...{ "OliveDrab",
"ForestGreen",
"DarkCyan",
"LightSlateGray",
"RoyalBlue",
"SlateBlue",
"DarkViolet",
"MediumVioletRed",
"IndianRed",
"Firebrick",
"Chocolate",
"Peru",
"Goldenrod"
};
private static Color BACkColor = Color.White;
private static Pen BorderColor = Pens.DarkGray;
private static int Width = 52;
private static int Height = 21;
private Random _random;
private String _code;
privatE int _brushNameIndex;
override protected void OnInit(EventArgs E)
...{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
//InitializeComponent();
//base.onInit(E);
}
/**//**//**//// <sumMary>
/// required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </sumMary>
private void InitializeComponent()
...{
//this.Load += new System.EventHandler(this.Page_Load);
}
/**//// <sumMary>
///
/// </sumMary>
/// <param name="sender"></param>
/// <param name="e"></param>
public void Page_Load(object sender,System.EventArgs E)
...{
if (!IsPostBACk)
...{
//
// TODO : initialize
//
this._random = new Random();
this._code = GetRandomCode();
//
// TODO : use Session["code"] save the VerifyCode
//
Session["code"] = this._code;
//
// TODO : output Image
//
this.SetPageNoCache();
this.OnPaint();
}
}
/**//**//**//// <sumMary>
/// 设置页面不被缓存
/// </sumMary>
private void SetPageNoCache()
...{
Response.buffer = true;
Response.ExpiresAbsolute = System.datetiR_146_11845@e.Now.AddSeconds(-1);
Response.Expires = 0;
Response.Cachecontrol = "no-cache";
Response.AppendHeader("Pragma","No-Cache");
}
/**//**//**//// <sumMary>
/// 取得一个 4 位的随机码
/// </sumMary>
/// <returns></returns>
private String GetRandomCode()
...{
return Guid.NewGuid().ToString().SubString(0,4);
}
/**//**//**//// <sumMary>
/// 随机取一个字体
/// </sumMary>
/// <returns></returns>
private Font GetFont()
...{
int fonTindex = _random.Next(0,FontItems.Length);
FontStyle fontStyle = GetFontStyle(_random.Next(0,2));
return new Font(FontItems[fonTindex],12,fontStylE);
}
/**//**//**//// <sumMary>
/// 取一个字体的样式
/// </sumMary>
/// <param name="index"></param>
/// <returns></returns>
private FontStyle GetFontStyle(int indeX)
...{
switch (indeX)
...{
case 0:
return FontStyle.bold;
case 1:
return FontStyle.Italic;
default:
return FontStyle.Regular;
}
}
/**//**//**//// <sumMary>
/// 随机取一个笔刷
/// </sumMary>
/// <returns></returns>
private Brush GetBrush()
...{
int brushIndex = _random.Next(0,BrushItems.Length);
_brushNameIndex = brushIndex;
return BrushItems[brushIndex];
}
/**//**//**//// <sumMary>
/// 绘画事件
/// </sumMary>
private void OnPaint()
...{
Bitmap objBitmap = null;
Graphics g = null;
try
...{
objBitmap = new Bitmap(Width,Height);
g = Graphics.FromImage(objBitmap);
PainT_Backg@R_607_7060@g);
Paint_Text(g);
Paint_TextStain(objBitmap);
PainT_Border(g);
objBitmap.Save(Response.outputStream,ImageFormat.Gif);
Response.ContentType = "image/gif";
}
catch ...{}
finally
...{
if (null != objBitmap)
objBitmap.Dispose();
if (null != g)
g.Dispose();
}
}
/**//**//**//// <sumMary>
/// 绘画背景颜色
/// </sumMary>
/// <param name="g"></param>
private void PainT_Backg@R_607_7060@Graphics g)
...{
g.Clear(BACkColor);
}
/**//**//**//// <sumMary>
/// 绘画边框
/// </sumMary>
/// <param name="g"></param>
private void PainT_Border(Graphics g)
...{
g.DrawRectangle(BorderColor,Width - 1,Height - 1);
}
/**//**//**//// <sumMary>
/// 绘画文字
/// </sumMary>
/// <param name="g"></param>
private void Paint_Text(Graphics g)
...{
g.DrawString(_code,GetFont(),GetBrush(),3,1);
}
/**//**//**//// <sumMary>
/// 绘画文字噪音点
/// </sumMary>
/// <param name="g"></param>
private void Paint_TextStain(Bitmap b)
...{
for (int n=0; n<30; n++)
...{
int x = _random.Next(Width);
int y = _random.Next(Height);
b.SetPixel(x,y,Color.Fromname(BrushName[_brushNameIndex]));
}
}
}