我实现的代码如下:
前台:
<IMG alt="看不清楚?请点击刷新验证码" src="ValidateCode.aspx" align="absMiddle" onclick="this.src='ValidateCode.aspx'"
style="CURSOR: pointer">
后台:
public class ValidateCode : System.Web.UI.Page
{
private void Page_Load(object sender, System.EventArgs e)
{
this.CreateCheckCodeImage(GenerateCheckCode());
// 在此处放置用户代码以初始化页面
}
private string GenerateCheckCode()
{ //产生五位的随机字符串
int number;
char code;
string checkCode = String.Empty; System.Random random = new Random(); for (int i = 0; i < 5; 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));
Session["CheckCode"] = checkCode;//用于客户端校验码比较 return checkCode;
} private void CreateCheckCodeImage(string checkCode)
{ //将验证码生成图片显示
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 < 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));
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();
}
}
第一次浏览,点击没反应.我点击确定之后,服务器验证.之后点击才会刷新.如何实现第一次浏览的时候就可以点击验证码图片刷新~?~~~
前台:
<IMG alt="看不清楚?请点击刷新验证码" src="ValidateCode.aspx" align="absMiddle" onclick="this.src='ValidateCode.aspx'"
style="CURSOR: pointer">
后台:
public class ValidateCode : System.Web.UI.Page
{
private void Page_Load(object sender, System.EventArgs e)
{
this.CreateCheckCodeImage(GenerateCheckCode());
// 在此处放置用户代码以初始化页面
}
private string GenerateCheckCode()
{ //产生五位的随机字符串
int number;
char code;
string checkCode = String.Empty; System.Random random = new Random(); for (int i = 0; i < 5; 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));
Session["CheckCode"] = checkCode;//用于客户端校验码比较 return checkCode;
} private void CreateCheckCodeImage(string checkCode)
{ //将验证码生成图片显示
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 < 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));
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();
}
}
第一次浏览,点击没反应.我点击确定之后,服务器验证.之后点击才会刷新.如何实现第一次浏览的时候就可以点击验证码图片刷新~?~~~
onclick="this.src='ValidateCode.aspx'"
后面几上一个随机参数比如this.src='ValidateCode.aspx'?abc=123"
其中的数字123用javascript来生成。(这个应该会巴),
就可以解决了