using System.Drawing;//实现验证码的过程利用了绘图功能public partial class CheckCode : System.Web.UI.Page
{ rivate String GenerateCheckCode()
{
int number;
char code;
string checkCode=String .Empty;
System .Random random=new Random ();
for (int i=0; i<6; 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 ["CheckCode"]=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 *13.5)),22);
Graphics g=Graphics .FromImage (image );
try
{
Random random=new Random ();
g.Clear(Color .White );
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 ,x2 ,y1 ,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 ();
}
}
}这是一个“验证码的实现”功能,谁能帮我看看错在哪了。。调试不出来
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private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
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;
}
--------------------------------------------------------------------------------------------------------------
(2)字符串生成后,接下来就是将该字符串绘制成图片显示出来。代码如下:
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 < 2; 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.Black), x1, y1, x2, y2);
} Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
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();
}
}
<img id="vcodeImg" src="about:blank" onerror="this.onerror=null;this.src='Validate.aspx'"
alt="验证码" title="看不清楚?换一张" style="cursor: pointer;" onclick="this.src=this.src+'?'+Math.random();" />-----------------------------------------------------------------------------------------------------------
最好引用比较的代码是: protected void Button1_Click(object sender, EventArgs e)
{
HttpCookie cookie = Request.Cookies["CheckCode"];
if (cookie.Value == this.txtCode.Text.Trim())
{
Response.Write("<script>alert('验证码正确!')</script>");
}
else
{
Response.Write("<script>alert('验证码错误!')</script>");
}
}
在pageload
if(!IsPostBack)
{
CreateCheckCodeImage(GenerateCheckCode());
}
你可以参考一下 ,我测试过没有问题,
有例子可以下载..