Question

asp.Net的验证码代码怎么写啊

Answer 1

主要代码如下:
// 生成随机数字字符串
public string GetRandomNumberString(int int_NumberLength)
{
string str_Number = string.Empty;
Random theRandomNumber = new Random();

for (int int_index = 0; int_index < int_NumberLength; int_index++)
str_Number += theRandomNumber.Next(10).ToString();

return str_Number;
}
生成随机颜色
public Color GetRandomColor()
{
Random RandomNum_First = new Random((int)DateTime.Now.Ticks);
// 对于C#的随机数，没什么好说的
System.Threading.Thread.Sleep(RandomNum_First.Next(50));
Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);

// 为了在白色背景上显示，尽量生成深色
int int_Red = RandomNum_First.Next(256);
int int_Green = RandomNum_Sencond.Next(256);
int int_Blue = (int_Red + int_Green > 400) ? 0 : 400 - int_Red - int_Green;
int_Blue = (int_Blue > 255) ? 255 : int_Blue;

return Color.FromArgb(int_Red, int_Green, int_Blue);
}
根据验证字符串生成最终图象
public void CreateImage(string str_ValidateCode)
{
int int_ImageWidth = str_ValidateCode.Length * 13;
Random newRandom = new Random();
// 图高20px
Bitmap theBitmap = new Bitmap(int_ImageWidth, 20);
Graphics theGraphics = Graphics.FromImage(theBitmap);
// 白色背景
theGraphics.Clear(Color.White);
// 灰色边框
theGraphics.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, int_ImageWidth - 1, 19);

// 10pt的字体
Font theFont = new Font("Arial", 10);

for (int int_index = 0; int_index < str_ValidateCode.Length; int_index++)
{
string str_char = str_ValidateCode.Substring(int_index, 1);
Brush newBrush = new SolidBrush(GetRandomColor());
Point thePos = new Point(int_index * 13 + 1 + newRandom.Next(3), 1 + newRandom.Next(3));
theGraphics.DrawString(str_char, theFont, newBrush, thePos);
}

// 将生成的图片发回客户端
MemoryStream ms = new MemoryStream();
theBitmap.Save(ms, ImageFormat.Png);

Response.ClearContent(); //需要输出图象信息 要修改HTTP头
Response.ContentType = "image/Png";
Response.BinaryWrite(ms.ToArray());
theGraphics.Dispose();
theBitmap.Dispose();
Response.End();
}

最后在Page_Load中调用以上代码

private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
{
// 4位数字的验证码
string str_ValidateCode = GetRandomNumberString(4);
// 用于验证的Session
Session["ValidateCode"] = str_ValidateCode;
CreateImage(str_ValidateCode);
}
}
使用的时候在页面中加入一个Image，将图片路径改为ValidateCode.aspx的相对路径即可

<img src="ValidateCode.aspx" />在需要验证的地方填入如下代码:
if (TextBox1.Text == Session["ValidateCode"].ToString())
{
TextBox1.Text = "正确!";
}
else
TextBox1.Text = "错误!";OK，基本搞定，总结一下：

Answer 2

新建个Code.asp，内容为

<%
Option Explicit
Response.buffer=true
NumCode
Function NumCode()
Response.Expires = -1
Response.AddHeader "Pragma"�6�5"no-cache"
Response.AddHeader "cache-ctrol"�6�5"no-cache"
dim zNum�6�5i�6�5j
dim Ados�6�5Ados1
Randomize timer
zNum = cint(8999*Rnd+1000)
Session("GetCode") = zNum
dim zimg(4)�6�5NStr
NStr=cstr(zNum)
For i=0 to 3
zimg(i)=cint(mid(NStr�6�5i+1�6�51))
Next
dim Pos
set Ados=Server.CreateObject("Adodb.Stream")
Ados.Mode=3
Ados.Type=1
Ados.Open
set Ados1=Server.CreateObject("Adodb.Stream")
Ados1.Mode=3
Ados1.Type=1
Ados1.Open
Ados.LoadFromFile(Server.mappath("images/body.Fix"))
Ados1.write Ados.read(1280)
for i=0 to 3
Ados.Position=(9-zimg(i))*320
Ados1.Position=i*320
Ados1.write ados.read(320)
next
Ados.LoadFromFile(Server.mappath("images/head.fix"))
Pos=lenb(Ados.read())
Ados.Position=Pos
for i=0 to 9 step 1
for j=0 to 3
Ados1.Position=i*32+j*320
Ados.Position=Pos+30*j+i*120
Ados.write ados1.read(30)
next
next
Response.ContentType = "image/BMP"
Ados.Position=0
Response.BinaryWrite Ados.read()
Ados.Close:set Ados=nothing
Ados1.Close:set Ados1=nothing
End Function
%>

再需要输出验证码的地方写
<img src=Code.asp>