生成验证码及在页面上无刷新更换代码,Asp.Net代码库,德仔网

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【Asp.Net】生成验证码及在页面上无刷新更换
作者:feige / 发布于2014/8/10/ 1085
无刷新更换

	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：
	<script language="javascript" type="text/javascript">
	function fresh()
	{
	var randomnum=Math.random();
	var getimagecode=document.getElementById( "codeimage");
	getimagecode.src= "ValidateImage.aspx? "+randomnum;
	}
	</script>
	
	
	
	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。
	<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>
	
	
	
	Validateimage.aspx页面是生成图片
	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();
	 }
	 }
试试其它关键字
　验证码　　无刷新更换　
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