例如可以用以下方法：

其中参数path所传递的值是所要查看的文件夹的绝对路径！

首先要导入System.IO

VB.NET

    '获取某个文件夹的大小
    Function getDirectorySize(ByVal path As String) As Long

        Dim dirInfo As New DirectoryInfo(path)
        Dim sumSize As Long = 0
        Dim fsInfo As FileSystemInfo
        For Each fsInfo In dirInfo.GetFileSystemInfos()
            If (fsInfo.Attributes.ToString.ToLower = "directory") Then
                sumSize += getDirectorySize(fsInfo.FullName)
            Else
                Dim fiInfo As New FileInfo(fsInfo.FullName)
                sumSize += fiInfo.Length
            End If
        Next
        getDirectorySize = sumSize

    End Function

C#

//获取某个文件夹的大小
public static long getDirectorySize(string path)
  {
  DirectoryInfo dirInfo=new DirectoryInfo(path);
  long sumSize=0;
  FileSystemInfo fsInfo;
  foreach(fsInfo in dirInfo.GetFileSystemInfos())
  {
  if(fsInfo.Attributes.ToString().ToLower() == "directory")
  {
  sumSize+=getDirectorySize(fsInfo.FullName);
  }
  else 
  {
  FileInfo fiInfo=new FileInfo(fsInfo.FullName);
  sumSize+=fiInfo.Length;
  }
  }
  return sumSize;
  } 
 关键字：ASP.NET  文件大小  文件夹大小  Directory  File