摘要:ashx檔中使用 BinaryWrite 下載檔案
	using System;
	using System.Web;
	using System.Data.SqlClient;
	using System.Data;
	using System.IO;
	using System.Configuration;
public class FileHandler : IHttpHandler {
	    public void ProcessRequest(HttpContext context)
	    {
	        try
	        {
	            //string Extension=Path.GetExtension("");//取得副檔名
	            string name = context.Request.QueryString["name"] as string;
	            context.Response.Buffer = true;
	            context.Response.Clear();
	            context.Response.ContentType = "application/download";
	            context.Response.AddHeader("Content-Disposition", "attachment;   filename=" + HttpUtility.UrlEncode(name, System.Text.Encoding.UTF8) + ";");
	            context.Response.BinaryWrite(File.ReadAllBytes(context.Server.MapPath(string.Format(@"images\{0}", name ) )   )    );
	            context.Response.Flush();
	            context.Response.End();
	        }
	        catch
	        {  }
	    }
	    public bool IsReusable
	    {
	        get
	        {
	            return false;
	        }
	    }
	
	}
資料來源http://www.dotblogs.com.tw/puma/archive/2009/02/12/7126.aspx