FileSystemInfo Class
One of the rich experiences in working with .NET is a huge collection of Base Class Libraries. The .NET Framework class library is a library of classes, interfaces, and value types that are included in the Microsoft .NET Framework SDK. This library provides access to system functionality and is designed to be the foundation on which .NET Framework applications, components, and controls are built.
System.IO namespace contains types that allow synchronous and asynchronous reading and writing on data streams and files.
To parse information of lots of files and directories, the FileSystemInfo class comes in handy. It is an abstract class and contains members (methods, properties …) that are common to file and directory manipulation. A FileSystemInfo object can represent either a file or a directory. The implementation of this abstract class is done in FileInfo and DirectoryInfo class. The Members would take full path (absolute or relative) or UNC path if they require path as one of the parameters.
In VB6 you could have used the Scripting Library (FileSystemObject) to manipulate the Files and directories.
Listing1: Members of FileSystemInfo class (for more information refer to MSDN)
| name | description |
| Attributes | Gets or sets the FileAttributes of the current FileSystemInfo. |
| CreationTime | Gets or sets the creation time of the current FileSystemInfo object |
| Exists | Gets a value indicating whether the file or directory exists |
| Extension | Gets the string representing the extension part of the file. |
| FullName | Gets the full path of the directory or file. |
| LastAccessTime | Gets or sets the time the current file or directory was last accessed |
| LastWriteTime | Gets or sets the time when the current file or directory was last written to. |
| Name | For files, gets the name of the file. For directories, gets the name of the last directory in the hierarchy if a hierarchy exists. Otherwise, the Name property gets the name of the directory |
| Delete | Deletes a file or directory. |
| FullPath | Represents the fully qualified path of the directory or file. |
| OriginalPath | The path originally specified by the user, whether relative or absolute. |
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The FileInfo class and DirectoryInfo class extends FileSystemInfo class and each add some more members to themselves for specific operations.
FileInfo Class
The FileInfo class provides instance methods for the creation, copying, deletion, moving, and opening of files, and provides members to create FileStream objects.
Listing2: List of some members of FileInfo class (for more information refer to MSDN). I have excluded the members of FileSystemInfo class overridden by FileInfo class and implemented by FileSystemInfo class.
| name | description |
| Directory | Gets an instance of the parent directory. |
| DirectoryName | Gets a string representing the directory's full path. |
| Length | Gets the size of the current file or directory. |
| Name | Gets the name of the file. |
| Create | Creates a file. |
| CreateText | Creates a StreamWriter that writes a new text file. |
| Open | Opens a file with various read/write and sharing privileges |
| OpenRead | Creates a read-only FileStream. |
| OpenText | Creates a StreamReader with UTF8 encoding that reads from an existing text file. |
| OpenWrite | Creates a write-only FileStream |
| AppendText | Creates a StreamWriter that appends text to the file represented by this instance of the FileInfo. |
| CopyTo | Copies an existing file to a new file. |
| MoveTo | Renames/moves an existing file. |
|
DirectoryInfo Class
The DirectoryInfo class provides instance methods for creating, moving, and enumerating through directories and subdirectories.
Listing3: List of some members of DirectoryInfo class (for more information refer to MSDN), I have excluded the members of FileSystemInfo Class overridden by Directory class and implemented by FileSystemInfo class.
| name | description |
| Parent | Gets the parent directory of a specified subdirectory. |
| Root | Gets the root portion of a path. |
| Create | Creates a directory. |
| CreateSubDirectory | Creates a subdirectory or subdirectories on the specified path. The specified path can be relative to this instance of the DirectoryInfo class. |
| GetDirectories | Returns the subdirectories of the current directory |
| GetFiles | Returns a file list from the current directory. |
| GetFileSystemInfos | Retrieves an array of strongly typed FileSystemInfo objects. |
| MoveTo | Moves a DirectoryInfo instance and its contents to a new path. |
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Below is an example of extending the FileSystemInfo class and adding IsDirectory and IsFile properties to it, new members can be added to roll a new custom class rather then using FileInfo or DirectoryInfo class. We can delegate most of the functionality to the FileInfo and DirectoryInfo classes in our custom class.
C# Implementation
using System;
using System.IO;
public class CFileSystem:FileSystemInfo
{
FileInfo mobjFileInfo;
DirectoryInfo mobjDirectoryInfo;
bool mblnIsDirectory = true;
public CFileSystem(string xstrFilePath)
{
try
{
mobjDirectoryInfo = new DirectoryInfo(xstrFilePath);
if (!(mobjDirectoryInfo.Extension.Length==0))
{
mblnIsDirectory = false;
mobjDirectoryInfo= null;
mobjFileInfo = new FileInfo(xstrFilePath);
}
}
catch (Exception ex)
{
Console.WriteLine( ex.ToString());
}
}
public override void Delete()
{
if (mblnIsDirectory)
{
mobjDirectoryInfo.Delete();
}
else
{
mobjFileInfo.Delete();
}
}
public override bool Exists
{
get
{
if (mblnIsDirectory)
{
return mobjDirectoryInfo.Exists;
}
else
{
return mobjFileInfo.Exists;
}
}
}
public string Fullname
{
get
{
if (mblnIsDirectory)
{
return mobjDirectoryInfo.FullName;
}
else
{
return mobjFileInfo.FullName;
}
}
}
public override string Name
{
get
{
if (mblnIsDirectory)
{
return mobjDirectoryInfo.Name;
}
else
{
return mobjFileInfo.Name;
}
}
}
public bool IsDirectory
{
get
{
return mblnIsDirectory;
}
}
public bool IsFile
{
get
{
return !mblnIsDirectory;
}
}
}
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VB.NET Implementation
Imports System.IO
Public Class CFileSystem
Inherits System.IO.FileSystemInfo
Private mobjFileInfo As FileInfo
Private mobjDirectoryInfo As DirectoryInfo
Private mblnIsDirectory As Boolean = True
Public Sub New(ByVal xstrFilePath As String)
Try
mobjDirectoryInfo = New DirectoryInfo(xstrFilePath)
If Not mobjDirectoryInfo.Extension().Length = 0 Then
mblnIsDirectory = False
mobjDirectoryInfo = Nothing
mobjFileInfo = New FileInfo(xstrFilePath)
End If
Catch ex As Exception
Console.WriteLine(ex.ToString)
End Try
End Sub
Public Overrides Sub Delete()
If mblnIsDirectory Then
mobjDirectoryInfo.Delete()
Else
mobjFileInfo.Delete()
End If
End Sub
Public Overrides ReadOnly Property Exists() As Boolean
Get
If mblnIsDirectory Then
Exists = mobjDirectoryInfo.Exists
Else
Exists = mobjFileInfo.Exists
End If
End Get
End Property
Public Overrides ReadOnly Property FullName() As String
Get
If mblnIsDirectory Then
FullName = mobjDirectoryInfo.FullName
Else
FullName = mobjFileInfo.FullName
End If
End Get
End Property
Public Overrides ReadOnly Property Name() As String
Get
If mblnIsDirectory Then
Name = mobjDirectoryInfo.Name
Else
Name = mobjFileInfo.Name
End If
End Get
End Property
Public ReadOnly Property IsDirectory() As Boolean
Get
IsDirectory = mblnIsDirectory
End Get
End Property
Public ReadOnly Property IsFile() As Boolean
Get
IsFile = mblnIsDirectory = False
End Get
End Property
End Class
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