通过webService下载sharepoint文档库文件

[WebMethod]
    public byte[]  GetAttachmentFileflow(string webPath,string list,int fileId) 
    {
        try
        {
            using (SPSite site = new SPSite(webPath))
            {
                SPWeb web = site.OpenWeb();
                SPList lists = web.Lists[list];
                SPListItem item = lists.Items.GetItemById(fileId);
                return item.File.OpenBinary();
            }

        }
        catch (Exception)
        {
            return new byte[] { };
        }
        
    }

protected void Page_Load(object sender, EventArgs e)
    {
        File.Delete(path);
        string webPath = "http://cntzmsw18:8099/";
        string list = "Shared Documents";
        localhost.Service server = new localhost.Service();
        byte[] b = server.GetAttachmentFileflow(webPath, list, 1594);//1594为文件ID通过SQL取得
        File.WriteAllBytes(path, b);
    }

    protected void BtnClick(object sender, EventArgs e)
    {
        FileStream fileStrem = new FileStream(path, FileMode.Open);
        long fileSize = fileStrem.Length;
        Context.Response.ContentType = "application/octet-stream";//设置报文
        Context.Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode("下载.docx", Encoding.UTF8));//下载文件名需要更改
        Context.Response.AddHeader("Content-Length", fileSize.ToString());
        byte[] fileBuffer = new byte[fileSize];
        fileStrem.Read(fileBuffer, 0, (int)fileSize);
        Context.Response.BinaryWrite(fileBuffer);
        fileStrem.Dispose();//释放资源
        Context.Response.End();
    }