asp.net 验证码 【Drawing.BitMap】
新建一个解决方案管理器---》添加--》新建网站---》asp.net空网站 。
在里面添加两个页（一个请求页面（Default.aspx），一个处理页面（VerifyCode.aspx））
请求页代码Default.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void BtnSubmit_Click(object sender, EventArgs e)
{
string txt = TxtCerifyCode.Text;
string vtxt = Session["code"].ToString();
string msg = "";
if (txt == vtxt) //如果你在txt(也就是TextBox1.Text)填入的值与在服务器端取到是值一致
{
msg = "验证码输入正确";
}
else
{
msg = "验证码错误";
}
ClientScript.RegisterClientScriptBlock(this.GetType(), "script0", "<script>alert('" + msg + "');</script>");
}
}
Default.aspx源代码
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_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></title>
<script type="text/javascript">
var refreshCode = function () {
document.getElementById('ImgVerifyCode').src = "VerifyCode.aspx";
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:TextBox runat="server" ID="TxtCerifyCode" />
<asp:Image ID="ImgVerifyCode" src="VerifyCode.aspx" runat="server" />
<a href="javascript:refreshCode()">刷新验证码</a>
<br /><br />
<asp:Button runat="server" ID="BtnSubmit" Text="提交" onclick="BtnSubmit_Click" />
</div>
</form>
</body>
</html>
处理页代码 VerifyCode.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Web.SessionState;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Text;
//这个页面仅仅是生成一副图片，并处理了这幅图片而已。
public partial class VerifyCode : System.Web.UI.Page
{
//定义一个字体数组
static string[] FontItems = new string[]
{
"Arial",
"Helvetica",
"Geneva",
"sans-serif",
"Verdana"
};
//定义一个画笔数组。
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
};
//定义一个颜色数组
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; //图片的宽度
private static int Height = 21; //图片的高度
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(); //取得一个 4 位的随机码
//
// TODO : use Session["code"] save the VerifyCode
//
Session["code"] = this._code; //将随机取得的 4 位的随机码添加到Session里面去 ，于是在请求页面(Default.aspx.cs)取得这个Sesssion的值就行了
//
// TODO : output Image
//
this.SetPageNoCache(); //设置页面不被缓存
this.OnPaint(); //绘画事件
}
}
/// <summary>
/// 设置页面不被缓存
/// </summary>
private void SetPageNoCache()
{
Response.Buffer = true;
Response.ExpiresAbsolute = System.DateTime.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_Background(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_Background(Graphics g)
{
g.Clear(BackColor); //清除绘图并以指定背景色填充
}
/// <summary>
/// 绘画边框
/// </summary>
/// <param name="g"></param>
private void Paint_Border(Graphics g)
{
g.DrawRectangle(BorderColor, 0, 0, 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]));
}
}
}