经过长时间学习VB.NET文件系统对象,于是和大家分享一下,看完本文你肯定有不少收获,希望本文能教会你更多东西。我们编程经常和VB.NET文件系统对象,比如获取硬盘的剩余空间、判断文件夹或文件是否存在等。在VB.NET文件系统对象(File System Object)没有推出以前,完成这些功能需要调用 Windows API 函数或者使用一些比较复杂的过程来实现,使编程复杂、可靠性差又容易出错。

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#T#使用 Windows 提供的的文件系统对象,一切变得简单多了。以下笔者举出一些编程中比较常用的例子,以函数或过程的形式提供给大家,读者可在编程中直接使用,也可以改进后实现更为强大的功能。要应用 FSO 对象,须要引用一个名为 Scripting 的类型库,方法是,执行 VB6.0 的菜单项“工程/引用”,添加引用列表框中的“Microsoft Scripting Runtime”一项。然后我们在“对象浏览器”中就可以看到 Scripting 类型库下的众多对象及其方法、属性。
1、判断光驱的盘符:
- Function GetCDROM() ' 返回光驱的盘符(字母)
 - Dim Fso As New FileSystemObject '创建 FSO 对象的一个实例
 - Dim FsoDrive As Drive, FsoDrives As Drives '定义驱动器、驱动器集合对象
 - Set FsoFsoDrives = Fso.Drives
 - For Each FsoDrive In FsoDrives '遍历所有可用的驱动器
 - If FsoDrive.DriveType = CDRom Then '如果驱动器的类型为 CDrom
 - GetCDROM = FsoDrive.DriveLetter '输出其盘符
 - Else
 - GetCDROM = ""
 - End If
 - Next
 - Set Fso = Nothing
 - Set FsoDrive = Nothing
 - Set FsoDrives = Nothing
 - End Function
 
2、判断文件、文件夹是否存在:
- '返回布尔值:True 存在,False 不存在,filername 文件名
 - Function FileExist(filename As String)
 - Dim Fso As New FileSystemObject
 - If Fso.FileExists(filename) = True Then
 - FileExist = True
 - Else
 - FileExist = False
 - End If
 - Set Fso = Nothing
 - End Function
 - '返回布尔值:True 存在,False 不存在,foldername 文件夹
 - Function FolderExist(foldername As String)
 - Dim Fso As New FileSystemObject
 - If Fso.FolderExists(foldername) = True Then
 - FolderExist = True
 - Else
 - FolderExist = False
 - End If
 - Set Fso = Nothing
 - End Function
 
3、获取驱动器参数:
- '返回磁盘总空间大小(单位:M),Drive = 盘符 A ,C, D ...
 - Function AllSpace(Drive As String)
 - Dim Fso As New FileSystemObject, Drv As Drive
 - Set Drv = Fso.GetDrive(Drive) '得到 Drv 对象的实例
 - If Drv.IsReady Then '如果该驱动器存在(软驱或光驱里有盘片,硬盘存取正常)
 - AllSpace = Format(Drv.TotalSize / (2 ^ 20), "0.00") '将字节转换为兆
 - Else
 - AllSpace = 0
 - End If
 - Set Fso = Nothing
 - Set Drv = Nothing
 - End Function
 - '返回磁盘可用空间大小(单位:M),Drive = 盘符 A ,C, D ...
 - Function FreeSpace(drive)
 - Dim Fso As New FileSystemObject, drv As drive
 - Set drv = Fso.GetDrive(drive)
 - If drv.IsReady Then
 - FreeSpace = Format(drv.FreeSpace / (2 ^ 20), "0.00")
 - End If
 - Set Fso = Nothing
 - Set Drv = Nothing
 - End Function
 - '获取驱动器文件系统类型,Drive = 盘符 A ,C, D ...
 - Function FsType(Drive As String)
 - Dim Fso As New FileSystemObject, Drv As Drive
 - Set Drv = Fso.GetDrive(Drive)
 - If Drv.IsReady Then
 - FsType = Drv.FileSystem
 - Else
 - FsType = ""
 - End If
 - Set Fso = Nothing
 - Set Drv = Nothing
 - End Function
 
4,获取系统文件夹路径:
- '返回 Windows 文件夹路径
 - Function GetWindir()
 - Dim Fso As New FileSystemObject
 - GetWindir = Fso.GetSpecialFolder(WindowsFolder)
 - Set Fso = Nothing
 - End Function
 - '返回 Windows\System 文件夹路径
 - Function GetWinSysdir()
 - Dim Fso As New FileSystemObject
 - GetWinSysdir = Fso.GetSpecialFolder(SystemFolder)
 - Set Fso = Nothing
 - End Function
 
5,综合运用:一个文件备份通用过程:
- 'Filename = 文件名,Drive = 驱动器,Folder = 文件夹(一层)
 - Sub BackupFile(Filename As String, Drive As String, Folder As String)
 - Dim Fso As New FileSystemObject '创建 FSO 对象实例
 - Dim Dest_path As String, Counter As Long
 - Counter = 0
 - Do While Counter < 6 '如果驱动器没准备好,继续检测。共检测 6 秒
 - CounterCounter = Counter + 1
 - Call Waitfor(1) '间隔 1 秒
 - If Fso.Drives(Drive).IsReady = True Then
 - Exit Do
 - End If
 - Loop
 - If Fso.Drives(Drive).IsReady = False Then '6 秒后目标盘仍未准备就绪,退出
 - MsgBox " 目标驱动器 " & Drive & " 没有准备好! ", vbCritical
 - Exit Sub
 - End If
 - If Fso.GetDrive(Drive).FreeSpace < Fso.GetFile(Filename).Size Then
 - MsgBox "目标驱动器空间太小!", vbCritical '目标驱动器空间不够,退出
 - Exit Sub
 - End If
 - If Right(Drive, 1) <> ":" Then
 - DriveDrive = Drive & ":"
 - End If
 - If Left(Folder, 1) <> "\" Then
 - Folder = "\" & Folder
 - End If
 - If Right(Folder, 1) <> "\" Then
 - FolderFolder = Folder & "\"
 - End If
 - Dest_path = Drive & Folder
 - If Not Fso.FolderExists(Dest_path) Then '如果目标文件夹不存在,创建之
 - Fso.CreateFolder Dest_path
 - End If
 - Fso.CopyFile Filename, Dest_path & Fso.GetFileName(Filename), True
 - '拷贝,直接覆盖同名文件
 - MsgBox " 文件备份完毕。", vbOKOnly
 - Set Fso = Nothing
 - End Sub
 - Private Sub Waitfor(Delay As Single) '延时过程,Delay 单位约为 1 秒
 - Dim StartTime As Single
 - StartTime = Timer
 - Do Until (Timer - StartTime) > Delay
 - Loop
 - End Sub
 
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