以往計算資料夾容量，需要使用迴圈計算檔案容量，然後在加起來，例如：

        private static void CalculateDirectorySize(string DirRoute, ref long totalSize)
        {
            foreach (string Route in Directory.EnumerateDirectories(DirRoute)) CalculateDirectorySize(Route, ref totalSize);
            foreach (FileInfo file in new DirectoryInfo(DirRoute).EnumerateFiles()) totalSize += file.Length;
        }

雖然可以計算，不過效率不太好，改用內建的 Scripting.FileSystemObject，速度會快上許多：

        private static long CalculateDirectorySize(string DirRoute)
        {
            try
            {
                Type tp = Type.GetTypeFromProgID("Scripting.FileSystemObject");
                object fso = Activator.CreateInstance(tp);
                object fd = tp.InvokeMember("GetFolder", BindingFlags.InvokeMethod, null, fso, new object[] { DirRoute });
                long ret = Convert.ToInt64(tp.InvokeMember("Size", BindingFlags.GetProperty, null, fd, null));
                Marshal.ReleaseComObject(fso);
                return ret;
            }
            catch
            {
                return 0;
            }
        }