一般驗證碼的產生方法都是相同的,主要的步驟都有兩步
第一步：隨機出一系統驗證碼的數字或字母，順便把隨機生成的數字或字母寫入Cookies 或者 Session。
第二步：用第一步隨機出來的數字或字母來合成圖片。
可以看出來驗證碼的複雜度主要是第二步來完成，你可以根據自己所要的複雜度來設定。
我們一起來看看：
第一步：隨機產生數字或字母的方法
/// <summary>
/// 生成验证码的随机数
/// </summary>
/// <returns>返回五位随机数</returns>
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
Random random = new Random();
for (int i = 0; i < 5; i++)//可以任意设定生成验证码的位数
{
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));//写入COOKIS
Session["CheckCode"] = checkCode; //写入Session，可以任意选一下
return checkCode;
}第二步：產生圖片
/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="checkCode"></param>
private void CreateCheckCodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
Bitmap image = new 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));
LinearGradientBrush brush = new 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);
MemoryStream ms = new MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{//释放对象资源
g.Dispose();
image.Dispose();
}*完整程式
先在裡面VS2005裡面的項目裡面加上一個加一個.aspx文件，在checkCode.aspx.cs 程式碼檔案中加入以下完整程式碼
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.IO;
using System.Drawing.Drawing2D;
public partial class checkCode : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
CreateCheckCodeImage(GenerateCheckCode());//调用下面两个方法;
}
/// <summary>
/// 生成验证码的随机数
/// </summary>
/// <returns>返回五位随机数</returns>
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
Random random = new Random();
for (int i = 0; i < 5; i++)//可以任意设定生成验证码的位数
{
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));//写入COOKIS
Session["CheckCode"] = checkCode; //写入Session，可以任意选一下
return checkCode;
}
/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="checkCode"></param>
private void CreateCheckCodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
Bitmap image = new 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));
LinearGradientBrush brush = new 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);
MemoryStream ms = new MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{//释放对象资源
g.Dispose();
image.Dispose();
}
}
}上面產生驗證碼的頁面都做好了，我們來呼叫看看：
在你需要用到驗證碼的地方加了Image控件
這樣驗證碼就會顯示到Image控制項上面了！
顯示弄好了，當然我們要判斷一下使用者的輸入是否正確！
只要我們取得使用者輸入的值跟Cookis或Session比較就OK了
取Cookies的值Request.Cookies["CheckCode"].Value
取Session的值Session["CheckCode"].Value
取Session的值Session["CheckCode"].Value
似乎)最好先判斷Session是否空）如果不要區分大小寫的話，就把用戶輸入的值和Cookies或Session的值都轉成大寫或都小寫 附用法protected void Button1_Click(object sender, EventArgs e)
{
if (Request.Cookies["CheckCode"].Value == TextBox1.Text.Trim().ToString())
{
Response.Write("Cookies is right");
}
else
{
Response.Write("Cookies is wrong");
}
if (Session["CheckCode"] != null)
{
if (Session["CheckCode"].ToString().ToUpper() == TextBox1.Text.Trim().ToString().ToUpper())
//这样写可以不能区分大小写
{
Response.Write("Session is right");
}
else
{
Response.Write("Session is wrong");
}
}
}
