1.建立一個一般處理常式
namespace WebApplication1{ /// <summary> /// $codebehindclassname$ 的摘要說明 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class Handler1 : IHttpHandler, IRequiresSessionState { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "image/gif"; //建立Bitmap對象，繪圖 Bitmap basemap = new Bitmap(100, 30); Graphics graph = Graphics.FromImage(basemap); graph.FillRectangle(new SolidBrush(Color.White), 0, 0, 100, 30); Font font = new Font(FontFamily.GenericSerif, 24, FontStyle.Bold, GraphicsUnit.Pixel); Random r = new Random(); string letters = "ABCDEFGHIJKLMNPQRSTUVWXYZ"; string letter; StringBuilder s = new StringBuilder(); //添加隨機的五個字母 for (int x = 0; x < 5; x++) { letter = letters.Substring(r.Next(0, letters.Length - 1), 1); s.Append(letter); graph.DrawString(letter, font, new SolidBrush(Color.Black), x * 19, r.Next(0, 8)); } //混淆背景 Pen linePen = new Pen(new SolidBrush(Color.Black), 2); for (int x = 0; x < 6; x++) graph.DrawLine(linePen, new Point(r.Next(0, 99), r.Next(0, 29)), new Point(r.Next(0, 99), r.Next(0, 29))); //將圖片儲存到輸出資料流中 basemap.Save(context.Response.OutputStream, ImageFormat.Gif); context.Session["CheckCode"] = s.ToString(); //如果沒有實現IRequiresSessionState，則這裡會出錯，也無法產生圖片 context.Response.End(); } public bool IsReusable { get { return false; } } }}
2.前台代碼
<html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div> <asp:TextBox ID="txtCode" runat="server"></asp:TextBox> <img id="imgCode" alt="看不清？點擊換一張" src="Handler1.ashx" style="cursor:pointer" onclick="this.src=this.src+'?'" /><br /> <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" /> </div> </form></body></html>
希望本文所述對大家asp.net程式設計有所協助。
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