System.IO.FileInfo file = new System.IO.FileInfo(fileName);
            if (file.Exists)
            {
                System.IO.FileStream fs = null;
                fs = System.IO.File.Open(fileName, System.IO.FileMode.Open);
                byte[] btFile = new byte[fs.Length];
                fs.Read(btFile, 0, Convert.ToInt32(fs.Length));
                fs.Close();

                System.Web.HttpContext.Current.Response.Clear();
                System.Web.HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);
                System.Web.HttpContext.Current.Response.AddHeader("Content-Length", file.Length.ToString());
                System.Web.HttpContext.Current.Response.ContentType = "audio/mpeg3";
                System.Web.HttpContext.Current.Response.BinaryWrite(btFile);
            }
            else
            {
                System.Web.HttpContext.Current.Response.Write("This file does not exist.");
            }

------解决方案--------------------
2）用hyperlink转到数据处理页，存储数据，用response.redirect("test.asp");转向链接页面，但也有问题，我的链接页面数据是从别人的数据库以xml形式得到的，如果只传ID，需要重新查找数据，运行很慢；如果所有数据都传过来，链接地址串又会超常，而且有非法字符。  

可以考虑用session传值
数据不是很大的话也可以用cookie

------解决方案--------------------

HTML code

<form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server" ScriptMode="Debug">
            <Services>
                <asp:ServiceReference Path="WebServiceFoundation.asmx" InlineScript="true" />
            </Services>
        </asp:ScriptManager>
        
        <input type="button" value="Get Random" onclick="getRandom()" />
        <input type="button" value="Get Range Random" onclick="getRandom(0, 9)" />
        
        <script language="javascript" type="text/javascript">
            function getRandom(minValue, maxValue)
            {
                if (arguments.length != 2)
                {
                    Sample.WebServiceFoundation.GetRandom(getRandomSucceeded);
                }
                else
                {
                    Sample.WebServiceFoundation.GetRangeRandom(minValue, maxValue, getRandomSucceeded);
                }
            }
            
            function getRandomSucceeded(result)
            {
                alert(result);
            }
        </script>
    </form>