使用IHttpHandler下载文件

namespace IBA.ECommerce.WebParts.UserControls
{
// <system.web>
// <httpHandlers>
// <add verb="GET,POST" path="GetImage.ashx" type="IBA.ECommerce.WebParts.UserControls.GetImageHandler"/>
// </httpHandlers>

public class GetImageHandler : IHttpHandler
{
#region IHttpHandler Members

public bool IsReusable
{
get { return false; }
}

public void ProcessRequest(HttpContext context)
{
Guid dociId = new Guid(context.Request["docid"]);
Document doc = Document.Get<Document>(dociId);
if (doc != null)
{
context.Response.ClearHeaders();

FileInfo fileInfo = new FileInfo(doc.FullPath);

context.Response.AddHeader("Content-Disposition", "attachment; filename=" + doc.Path2);
context.Response.TransmitFile(doc.FullPath);

context.Response.End();
}
}

#endregion
}
}