sharepoint-正则表达式在文档库取文件

[WebMethod]
    public byte[] GetAttachmentFileflowByName(string webPath, string listName, string regular)
    {
        try
        {
            using (SPSite site = new SPSite(webPath))
            {
                SPWeb web = site.OpenWeb();
                SPFolder folder= web.Folders[listName];
                if (folder!=null)
                {
                    SPFile file = GetFileFormFolder(folder, regular);
                    if (file!=null)
                    {
                        return file.OpenBinary();
                    }
                }
                return new byte[] { };
            }
        }
        catch (Exception)
        {
            return new byte[] { };
        }
    }
    /// <summary>
    /// 在SPFolder中寻找指定regular文件
    /// </summary>
    /// <param name="folder"></param>
    /// <param name="regular"></param>
    /// <returns>返回SPFile如无则返回null</returns>
    public SPFile GetFileFormFolder(SPFolder folder, string regular) 
    {
        if (folder.Files.Count>0)
        {
            foreach (SPFile file in folder.Files)
            {
                if (System.Text.RegularExpressions.Regex.IsMatch(file.Name, regular))
                {
                    return file;
                }
            }
        }
        if (folder.SubFolders.Count>0)
        {
            foreach (SPFolder iFolder in folder.SubFolders)
            {
                if (GetFileFormFolder(iFolder, regular)!=null)
                {
                    return GetFileFormFolder(iFolder, regular);
                }
            }
        }
        return null;
    }