Sharepoint 下载 文档库文件（转成字节下载）

由于SharePoint和Office集成得很紧密，所以当用户采取下载副本的时候，会有一个打开按钮，当点击打开的时候可以直接打开，并直接修改文档里的内容，而不经过审批，帮采用自定义的代码来下载，让其不能在线保存，不能直接把File直接Response出去，帮需要把File转成字节输出去，下面是代码的简单示例，不是完善的代码

    SPWeb web = SPContext.Current.Web;
            web.AllowUnsafeUpdates = true;
            SPList list = web.Lists["testDoc"];
            SPListItem item = list.GetItemById(3);
            string strPath = web.Url + "/" + list.RootFolder.Url + "/" + item.Name;
            //Response.Write("strPath:" + strPath + "<br/>");
            SPFile tempFile=web.GetFile(strPath);
            byte[] obj = (byte[])tempFile.OpenBinary();           
            //list.BrowserFileHandling = SPBrowserFileHandling.Permissive;
            Response.ClearContent();
            Response.ClearHeaders();
            Response.AppendHeader("Content-Disposition", "attachment; filename= " + System.Web.HttpUtility.UrlEncode(tempFile.Name));
            Response.ContentType = "application/msword"; 
            Response.BinaryWrite(obj);
            Response.Flush();
            Response.Close();