我知道以下两种方法

方法1：来自MSDN http://msdn.microsoft.com/en-us/library/system.io.directory.aspx

‘以下示例计算目录的大小
‘及其子目录(如果有),并显示总大小
‘以字节为单位.

Imports System
Imports System.IO

Public Class ShowDirSize

Public Shared Function DirSize(ByVal d As DirectoryInfo) As Long
    Dim Size As Long = 0
    ' Add file sizes.
    Dim fis As FileInfo() = d.GetFiles()
    Dim fi As FileInfo
    For Each fi In fis
        Size += fi.Length
    Next fi
    ' Add subdirectory sizes.
    Dim dis As DirectoryInfo() = d.GetDirectories()
    Dim di As DirectoryInfo
    For Each di In dis
        Size += DirSize(di)
    Next di
    Return Size
End Function 'DirSize

Public Shared Sub Main(ByVal args() As String)
    If args.Length <> 1 Then
        Console.WriteLine("You must provide a directory argument at the command line.")
    Else
        Dim d As New DirectoryInfo(args(0))
        Dim dsize As Long = DirSize(d)
        Console.WriteLine("The size of {0} and its subdirectories is {1} bytes.",d,dsize)
    End If
End Sub 'Main
End Class 'ShowDirSize

方法2：从What’s the best way to calculate the size of a directory in .NET?开始

Dim size As Int64 = (From strFile In My.Computer.FileSystem.GetFiles(strFolder,_
              FileIO.SearchOption.SearchAllSubDirectories) _
              Select New System.IO.FileInfo(strFile).Length).Sum()

这两种方法都很好.但是,如果存在大量子文件夹,则需要花费大量时间来计算目录大小.例如,我有一个包含150,000个子文件夹的目录.上述方法花了大约1小时30分钟来计算目录的大小.但是,如果我从窗户检查尺寸不到一分钟.

请建议更好,更快的方法来计算目录的大小.