ASP.NET 验证码示例
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ASP.NET 验证码示例
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<%@?Page?Language="C#"?%>
<%@?Import?Namespace="System.Drawing"?%>
<!DOCTYPE?html?PUBLIC?"-//W3C//DTD?XHTML?1.0?Transitional//EN"?"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">?
<!--
????1.準備Bitmap對象?image:
????????System.Drawing.Bitmap?image?=?new?System.Drawing.Bitmap(iwidth,?20);
????2.利用Graphics對象g在上面畫圖:
????????Graphics?g?=?Graphics.FromImage(image);?
????????g.DrawString(checkCode,?f,?b,?3,?3);?
????3.然后Response.BinaryWrite輸出:
????????Response.BinaryWrite(ms.ToArray());
????優化想法：
????將驗證碼以js腳本可讀取的方式發送到客戶端；
????客戶端先出發js腳本的驗證，通過后才允許提交；
????提供重新獲取驗證碼功能。
-->
<script?runat="server">
????????///?<summary>
????????///?輸入要求的驗證碼的位數，返回一個驗證碼字符串
????????///?</summary>
????????///?<param?name="codeCount">驗證碼的位數</param>
????????///?<returns>驗證碼字符串</returns>
????????private?string?CreateRandomCode(int?codeCount)
????????{
????????????string?allChar?=?"0,1,2,3,4,5,6,7,8,9,"?+
????????????????"A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,"?+
????????????????"a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z";
????????????string[]?allCharArray?=?allChar.Split(',');
????????????int?allCharLen?=?allCharArray.Length;?
????????????string?randomCode?=?"";?
????????????Random?rand?=?new?Random();
????????????for?(int?i?=?0;?i?<?codeCount;?i++)
????????????{
????????????????randomCode?+=?allCharArray[rand.Next(0,?allCharLen)];
????????????}
????????????return?randomCode;
????????}
????
????????///?<summary>
????????///?根據驗證碼checkCode畫圖
????????///?</summary>
????????///?<param?name="checkCode"></param>
????????private?void?CreateImage(string?checkCode)
????????{
????????????int?iwidth?=?(int)(checkCode.Length?*?11.5);
????????????System.Drawing.Bitmap?image?=?new?System.Drawing.Bitmap(iwidth,?20);
????????????Graphics?g?=?Graphics.FromImage(image);
????????????Font?f?=?new?System.Drawing.Font("Arial",?10,?System.Drawing.FontStyle.Bold);
????????????Brush?b?=?new?System.Drawing.SolidBrush(Color.White);
????????????//g.FillRectangle(new?System.Drawing.SolidBrush(Color.Blue),0,0,image.Width,?image.Height);
????????????g.Clear(Color.Blue);
????????????g.DrawString(checkCode,?f,?b,?3,?3);?
????????????g.Dispose();
????????????//Pen?blackPen?=?new?Pen(Color.Black,?0);
????????????//Random?rand?=?new?Random();
????????????//for?(int?i?=?0;?i?<?5;?i++)
????????????//{
????????????//????int?y?=?rand.Next(image.Height);
????????????//????g.DrawLine(blackPen,?0,?y,?image.Width,?y);
????????????//}?
????????????System.IO.MemoryStream?ms?=?new?System.IO.MemoryStream();
????????????image.Save(ms,?System.Drawing.Imaging.ImageFormat.Jpeg);
????????????Response.ClearContent();
????????????Response.ContentType?=?"image/Jpeg";
????????????Response.BinaryWrite(ms.ToArray());
????????????image.Dispose();
????????????//---------緩存驗證碼，以備驗證---------
????????????Session["ValidateCode"]?=?checkCode;
????????????/*如果希望在掛接該aspx頁的頁面A.aspx內執行Session的綁定就是白扯！
?????????????*?A頁面首先綁定，然后是確定表達式，此時B.aspx未執行，還沒有產生Session呢！
?????????????*?*/
????????}?????
????????protected?void?Page_Load(object?sender,?EventArgs?e)
????????{
????????????CreateImage(CreateRandomCode(6));
????????}
</script>?
<html?xmlns="http://www.w3.org/1999/xhtml"?>
<head?id="Head1"?runat="server">
????<title>無標題頁</title>
</head>
<body>
</body>
</html>
調用上面的驗證程序：
<%@?Page?Language="C#"?%>?
<!DOCTYPE?html?PUBLIC?"-//W3C//DTD?XHTML?1.0?Transitional//EN"?"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">?
<script?runat="server">?
????protected?void?btnSend_Click(object?sender,?EventArgs?e)
????{
????????if(Session["ValidateCode"].ToString()!=txtValidateCode.Text)
????????Response.Write("驗證碼不正確");
????????else
????????Response.Write("登錄到新的界面！");
????}
</script>?
<html?xmlns="http://www.w3.org/1999/xhtml"?>
<head?id="Head1"?runat="server">
????<title>無標題頁</title>
</head>
<body>
????<form?id="form1"?runat="server">
????????<div>
????????<asp:TextBox?ID="txtValidateCode"?runat="server"></asp:TextBox>
????????
????????<img?src="ValidateCode.aspx"?alt="驗證碼"?/>
????????<br?/>
????????<asp:Button?ID="btnSend"?runat="server"?OnClick="btnSend_Click"?Text="發送"?/></div>
????</form>
</body>
</html>
轉載于:https://www.cnblogs.com/flaaash/archive/2007/12/14/995173.html
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