In VB6, you often need to implement file search facilities in your applications. For instance, you might need to search for a particular log file on the client machine, get a listing of all files available in the particular directory, or verify that a particular directory or file exists. The simplest way to achieve this is to employ the FileSystemObject component, which provides a useful set of features that can simplify coding.
FileSystemObject componentThe FileSystemObject gives you access to the file system. It allows creating, manipulating, deleting, and obtaining information about drives, folders, and files. To use FileSystemObject in your VB code, you need to declare it in the following way:
Dim fso As New FileSystemObjectYou can then use its properties and methods, which are shown in
Table A.
Table A | Object/collection | Type | Description | | FileSystemObject | Main object | Allows creating, deleting, manipulating, and getting information about drives, folders, files | | Drive | Object | Allows getting information about a drive | | Drives | Collection | Lists drives available on the system (both physical and logical) | | File | Object | Allows creating, deleting, and moving files, as well as getting file properties | | Files | Collection | Lists all files in a given folder | | Folder | Object | Allows creating, moving, and deleting folders, as well as getting information about a particular folder | | Folders | Collection | Provides a list of all folders in a Folder | | TextStream | Object | Allows reading and writing text files | |
FileSystemObject object modelTable B outlines the most often used methods of the FileSystemObject.
Table B Method
| Description
| Example
| CreateFolder
| Creates a new folder
| fso.CreateFolder "C:\Files"
| CreateTextFile
| Creates a specified filename and returns a TextStream object that can be used to read from or write to the file
| fso.CreateTextFile "C:\Files\file1.txt"
| DeleteFolder
| Deletes folder
| fso.DeleteFolder "C:\Files"
| DeleteFile
| Deletes file
| fso.DeleteFile "C:\Files.file.txt"
| CopyFolder
| Copies a folder and its contents to another folder
| fso.CopyFolder "C:\Files", "C:\Files_Copy"
| CopyFile
| Copies a file to another location
| fso.CopyFile "C:\Files\file.txt", "C:\Files\file_copy.txt"
| MoveFolder
| Moves a folder to another location
| fso.MoveFolder "C:\Files", "C:\Files Move"
| MoveFile
| Moves a file to another location
| fso.MoveFile "C:\Files\file.txt", "C:\Files\file_move.txt"
| GetDrive
| Returns a Drive object corresponding to the drive in a specified path. Allows getting various information about the drive, such as available space, drive letter, drive type, file system, free space, serial number, share name, total size
| fso.GetDrive("C") AvailableSpace
| DriveExists
| Checks whether a drive exists
| If fso.DriveExists("D") Then
MsgBox "Drive D found"
End If
| GetFolder
| Returns a Folder object corresponding to the folder in a specified path
| fso.GetFolder(app.Path)
| GetParentFolderName
| Returns a string containing the name of the parent folder of the last component in a specified path | fso.GetParentFolderName(app.Path)
| GetSpecialFolder
| Returns the special folder specified. One of three options: WindowsFolder (contains files installed by the Windows operating system), SystemFolder (contains fonts, libraries, device drivers), or TemporaryFolder (used to store temp files)
| fso.GetSpecialFolder(TemporaryFolder)
| GetFile
| Returns a File object corresponding to the file in a specified path | .GetFile "C:\Files\file.txt"
| FolderExists
| Checks whether a folder exists
| If fso.FolderExists("C:\Files") Then
MsgBox "Folder Exists!"
End If
| FileExists
| Checks whether a file exists
| If fso.FileExists("C:\Files\file.txt") Then
MsgBox "File Exists!"
End if
| |
Common FileSystemObject methodsCode exampleLet’s take a look at the code that will allow you to go through files in a specified directory and list them in a Listbox control. We'll assume that you have a Listbox control on a form called lstFiles
and a C:\Files directory on your system that contains a number of files.
Listing A shows the code to retrieve a list of those files.
FileSystemObject limitationsWhen you implement FileSystemObject, you should keep in mind these limitations:
- · FileSystemObject allows creating ASCII or Unicode text files.
- · FileSystemObject can read only ASCII text files.
- · When reading files, FileSystemObject can read in only one direction and only line by line.
- · A file can’t be open for reading and writing. You can open a file in ForReading mode using OpenTextFile, but to make changes to the file, you would need to open a TextStream object.
- · When searching for files, you can’t use wildcards; you must specify the exact name.
- · When retrieving filenames from the files collection, filenames can’t be sorted. To return them in a specific order, you must add a subroutine to do it.
ConclusionIn this article, we demonstrated a simple way to implement a file search, copy, move, and delete files and folders, and other useful features using FileSystemObject. Next time, we will look at other code examples that will simplify your code.
