放验证码的页面内添加如下js脚本,这个是刷新验证码的方法:
代码语言:javascript复制<script language="javascript" type="text/javascript">
function fresh()
{
var randomnum=Math.random();
var getimagecode=document.getElementById( "codeimage");
getimagecode.src= "ValidateImage.aspx? " randomnum;
}
</script>
//该代码片段来自于: http://www.sharejs.com/codes/csharp/7816
页面内要放验证码的地方(层内,单元格内等)放置如下代码,这个是验证码的图图,输入验证码的文本框和调刷新方法的链接。
代码语言:javascript复制<div><img id="codeimage" src="ValidateImage.aspx?,Math.random()" />
<asp:TextBox ID="txtValidateCode" runat="server" Width="55px" MaxLength="4"></asp:TextBox>
<a href="javascript:fresh()" style="font-size: 12px; color: Green">看不清</a></div>
//该代码片段来自于: http://www.sharejs.com/codes/csharp/7816
Validateimage.aspx页面是生成图片
代码语言:javascript复制private void Page_Load(object sender, System.EventArgs e)
{
this.CreateCheckCodeImage(RndNum());
}
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("yzmcode", 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 * 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 < 20; 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.Aqua), 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.BlueViolet, Color.BlueViolet, 1.2f, true);
g.DrawString(checkCode, font, brush, 2, 2);
//画图片的前景噪音点
for (int i = 0; i < 50; 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();
}
}