file的name值

在picturelibrary中取一张jpg文件, 其Name值为  "NoThumbnail.jpg",注意后面的.jpg
            foreach (SPFile item in rootFolder.Files)
            {
                if (item.Name == "NoThumbnail.jpg")
                {
                    NoThumbnailUrl = item.ServerRelativeUrl;
                }
            }