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.Design;
using System.Drawing;
using System.Text;
namespace Webform
{
public partial class imgCheck : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
this.CreateCheckCodeImage(RndNumcn2());
}
//隨機字母的簡單演算法
private string RndNum()
{
int number;
char code;
string checkCode = String.Empty;
System.Random random = new Random();
for (int i = 0; i < 4; 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));
return checkCode;
}
//簡單的隨機漢字演算法
private string RndNumcn()
{
string letters = "我愛你豬寶貝";
string letter;
string checkCode = "";
System.Random r = new Random();
for (int x = 0; x < 2; x++)
{
letter = letters.Substring(r.Next(0, letters.Length - 1), 1);
checkCode += letter;
}
Response.Cookies.Add(new HttpCookie("checkCode", checkCode));
return checkCode;
}
//複雜隨機漢字演算法
private string RndNumcn2()
{
Encoding gb = Encoding.GetEncoding("gb2312");
//呼叫函式產生4個隨機中文漢字編碼
object[] bytes = CreateRegionCode(4);
//根據漢字編碼的位元組陣列解碼出中文漢字
string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[])));
string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[])));
string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[])));
string str4 = gb.GetString((byte[])Convert.ChangeType(bytes[3], typeof(byte[])));
string checkCode= (str1 + str2 + str3 + str4);
Response.Cookies.Add(new HttpCookie("checkCode", checkCode));
return checkCode;
}
public static object[] CreateRegionCode(int strlength)
{
//定義一個字串陣列儲存漢字編碼的組成元素
string[] rBase=new String [16]{"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};
Random rnd=new Random();
//定義一個object陣列用來
object[] bytes=new object[strlength];
/**//*每迴圈一次產生一個含兩個元素的十六進位制位元組陣列，並將其放入bject陣列中
每個漢字有四個區位碼組成
區位碼第1位和區位碼第2位作為位元組陣列第一個元素
區位碼第3位和區位碼第4位作為位元組陣列第二個元素
*/
for(int i=0;i<strlength;i++)
{
//區位碼第1位
int r1=rnd.Next(11,14);
string str_r1=rBase[r1].Trim();
//區位碼第2位
rnd=new Random(r1*unchecked((int)DateTime.Now.Ticks)+i);//更換隨機數發生器的種子避免產生重複值
int r2;
if (r1==13)
{
r2=rnd.Next(0,7);
}
else
{
r2=rnd.Next(0,16);
}
string str_r2=rBase[r2].Trim();
//區位碼第3位
rnd=new Random(r2*unchecked((int)DateTime.Now.Ticks)+i);
int r3=rnd.Next(10,16);
string str_r3=rBase[r3].Trim();
//區位碼第4位
rnd=new Random(r3*unchecked((int)DateTime.Now.Ticks)+i);
int r4;
if (r3==10)
{
r4=rnd.Next(1,16);
}
else if (r3==15)
{
r4=rnd.Next(0,15);
}
else
{
r4=rnd.Next(0,16);
}
string str_r4=rBase[r4].Trim();
//定義兩個位元組變數儲存產生的隨機漢字區位碼
byte byte1=Convert.ToByte(str_r1 + str_r2,16);
byte byte2=Convert.ToByte(str_r3 + str_r4,16);
//將兩個位元組變數儲存在位元組陣列中
byte[] str_r=new byte[]{byte1,byte2};
//將產生的一個漢字的位元組陣列放入object陣列中
bytes.SetValue(str_r,i);
}
return bytes;
}
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 * 22.5)), 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片背景色
g.Clear(Color.White);
//畫圖片的背景噪音線
for (int i = 0; i < 8; 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);
//畫圖片的前景噪音點
for (int i = 0; i < 10; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//畫圖片的邊框線
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();
}
}
}
}
客戶端測試：
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<div>
<asp:ImageButton ID="yzm" runat="server" ImageUrl="imgcheck.aspx" />
<asp:LinkButton ID="ChangeCode" runat="server" Text="看不清楚？換一個驗證碼" />
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" /></div>
if (String.Compare(Request.Cookies["checkCode"].Value, TextBox1.Text, true) != 0)
{
Response.Write("<script>alert('驗證碼錯誤!')</script>");
}
else
{
Response.Write("<script>alert('驗證嗎正確!!!')</script>");
}