VB.NET TUTORIALS - VB.Net - File Handling

VB.Net - File Handling

VB.Net I/O Classes

I/O Class	Description
BinaryReader	Reads primitive data from a binary stream.
BinaryWriter	Writes primitive data in binary format.
BufferedStream	A temporary storage for a stream of bytes.
Directory	Helps in manipulating a directory structure.
DirectoryInfo	Used for performing operations on directories.
DriveInfo	Provides information for the drives.
File	Helps in manipulating files.
FileInfo	Used for performing operations on files.
FileStream	Used to read from and write to any location in a file.
MemoryStream	Used for random access of streamed data stored in memory.
Path	Performs operations on path information.
StreamReader	Used for reading characters from a byte stream.
StreamWriter	Is used for writing characters to a stream.
StringReader	Is used for reading from a string buffer.
StringWriter	Is used for writing into a string buffer.

The FileStream Class

Parameter	Description
FileMode	The FileMode enumerator defines various methods for opening files. The members of the FileMode enumerator are: Append: It opens an existing file and puts cursor at the end of file, or creates the file, if the file does not exist. Create: It creates a new file. CreateNew: It specifies to the operating system that it should create a new file. Open: It opens an existing file. OpenOrCreate: It specifies to the operating system that it should open a file if it exists, otherwise it should create a new file. Truncate: It opens an existing file and truncates its size to zero bytes.
FileAccess	FileAccess enumerators have members: Read, ReadWrite and Write.
FileShare	FileShare enumerators have the following members: Inheritable: It allows a file handle to pass inheritance to the child processes None: It declines sharing of the current file Read: It allows opening the file for reading ReadWrite: It allows opening the file for reading and writing Write: It allows opening the file for writing

Parameter

Description

FileMode

The FileMode enumerator defines various methods for opening files. The members of the FileMode enumerator are:

Append: It opens an existing file and puts cursor at the end of file, or creates the file, if the file does not exist.
Create: It creates a new file.
CreateNew: It specifies to the operating system that it should create a new file.
Open: It opens an existing file.
OpenOrCreate: It specifies to the operating system that it should open a file if it exists, otherwise it should create a new file.
Truncate: It opens an existing file and truncates its size to zero bytes.

FileAccess

FileAccess enumerators have members: Read, ReadWrite and Write.

FileShare

FileShare enumerators have the following members:

Inheritable: It allows a file handle to pass inheritance to the child processes
None: It declines sharing of the current file
Read: It allows opening the file for reading
ReadWrite: It allows opening the file for reading and writing
Write: It allows opening the file for writing

Advanced File Operations in VB.Net

Topic and Description
Reading from and Writing into Text files It involves reading from and writing into text files. The StreamReader and StreamWriter classes help to accomplish it.
Reading from and Writing into Binary files It involves reading from and writing into binary files. The BinaryReader and BinaryWriter classes help to accomplish this.
Manipulating the Windows file system It gives a VB.Net programmer the ability to browse and locate Windows files and directories.

The FileStream Class

Dim <object_name> As FileStream = New FileStream(<file_name>, <FileMode Enumerator>, <FileAccess Enumerator>, <FileShare Enumerator>)

						
Dim f1 As FileStream = New FileStream("test.dat", FileMode.OpenOrCreate, FileAccess.ReadWrite)

						Example:

Imports System.IO
Module fileProg
   Sub Main()
      Dim f1 As FileStream = New FileStream("test.dat", _
              FileMode.OpenOrCreate, FileAccess.ReadWrite)
      Dim i As Integer
      For i = 0 To 20
          f1.WriteByte(CByte(i))
      Next i
      f1.Position = 0
      For i = 0 To 20
          Console.Write("{0} ", f1.ReadByte())
      Next i
      f1.Close()
      Console.ReadKey()
   End Sub
End Module