ASP.net实现验证码技术（网上收集)
第一步生成验证码
新增一个ValidateCode.aspx页面
在ValidateCode.aspx.cs的代码如下
using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;
using System.Drawing.Imaging;
public partial class ValidateCode : System.Web.UI.Page
{ //该页面将用于生成验证码图片
protected void Page_Load(object sender, EventArgs e)
{ //调用函数将验证码生成图片
this.CreateCheckCodeImage(GenerateCheckCode());
}
private string GenerateCheckCode()
{ //产生五位的随机字符串
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();
}
//Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
Session["CheckCode"] = checkCode;//用于客户端校验码比较
return checkCode;
}
private void CreateCheckCodeImage(string checkCode)
{ //将验证码生成图片显示
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();
}
}
}
第二步测试验证码
建立Test.aspx
form id="form1" runat="server">
<div>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" /><br />
<asp:Image ID="Image1" runat="server" ImageUrl="~/ValidateCode.aspx" />//该图片将用于显示验证码
</div>
</form>
Test.aspx.cs代码
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (this.TextBox1.Text.ToString().Trim() == Session["CheckCode"].ToString()) { Response.Write("<script lauguage='javascript'>alert('验证成功');</script>"); }
}
