生成验证码
checkcode.x页面其实什么也不用写
<%@ page language="c#" codefile="checkcode.aspx.cs" inherits="validatecode" %>
<!doctype html public "-//w3c//dtd xhtml 1.1//en" "http://www.w3.org/tr/xhtml11/dtd/xhtml11.dtd">
<html xmlns="">
<head runat="server">
<title>untitled page</title>
</head>
<body>
<form id="form1" runat="server">
</form>
</body>
</html>
checkcode.aspx.cs页面代码，生成验证码的主要部分
using system;
using system.data;
using system.configuration;
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;
public partial class validatecode : system.web.ui.page
{
private void page_load(object sender, system.eventargs e)
{
this.createcheckcodeimage(generatecheckcode());
}
#region web 窗体设计器生成的代码
override protected void oninit(eventargs e)
{
//
// codegen: 该调用是 asp.net web 窗体设计器所必需的。
//
initializecomponent();
base.oninit(e);
}
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void initializecomponent()
{
this.load += new system.eventhandler(this.page_load);
}
#endregion
private string generatecheckcode()
{
int number;
char code;
string checkcode = string.empty;
system.random random = new random();
for (int i = 0; i < 5; i++)
{
number = random.next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('a' + (char)(number % 26));
checkcode += code.tostring();
}
session["checkcodeimage"] = checkcode;
return checkcode;
}
private void createcheckcodeimage(string checkcode)
{
if (checkcode == null || checkcode.trim() == string.empty)
return;
system.drawing.bitmap image = new system.drawing.bitmap((int)math.ceiling((checkcode.length * 12.5)), 22);
graphics g = graphics.fromimage(image);
try
{
//生成随机生成器
random random = new random();
//清空图片背景色
g.clear(color.white);
//画图片的背景噪音线
for (int i = 0; i < 25; 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.silver), x1, y1, x2, y2);
}
font font = new system.drawing.font("arial", 12, (system.drawing.fontstyle.bold | system.drawing.fontstyle.italic));
system.drawing.drawing2d.lineargradientbrush brush = new system.drawing.drawing2d.lineargradientbrush(new rectangle(0, 0, image.width, image.height), color.blue, color.darkred, 1.2f, true);
g.drawstring(checkcode, font, brush, 2, 2);
//画图片的前景噪音点
for (int i = 0; i < 100; i++)
{
int x = random.next(image.width);
int y = random.next(image.height);
image.setpixel(x, y, color.fromargb(random.next()));
}
//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());
}
finally
{
g.dispose();
image.dispose();
}
}
}
下一步我们来引用上面的生成验证码页面（太简单不多说）
<asp:label id="labflag" runat="server" text="label"></asp:label>
<asp:textbox id="txtyz_code" runat="server" maxlength="5" width="55px" bordercolor="gray" borderwidth="1px"></asp:textbox>
<img title="看不清点击换一张" align="absmiddle" onclick="this.src=this.src+'?'" src="password/checkcode.aspx" />
后台判断
if (string.compare(session["checkcodeimage"].tostring(), this.txtyz_code.text.trim().toupper(), true) != 0)
{
this.labflag.text = "验证码错误，请输入正确的验证码。";
}
摘自 爱智旮旯