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1. Chapter five
Manipulating Files (File handling)
Introduction
 Most applications require data to be stored in files
 Spreadsheets
 Word processing
 etc
 File - is a collection of data stored in a disk with a specific name and a directory path.
 When a file is opened for reading or writing, it becomes a stream.
 Stream - is basically the sequence of bytes passing through the communication path.
There are two main streams: input and output stream.
 Input stream - used for reading data/byte stream from file (read operation) and
 Output stream - used for writing data/byte stream into the file (write operation).
 input and output stream objects are created from class FileStream
System.IO Namespace

2. File Manipulation Activities
 Open a file, reading a file, writing a file, appending a text to a file, copying a file, moving a
file, and Deleting a file.
 The System.IO namespace has various classes that are used for performing
various operations with files, like creating and deleting files, reading from or writing
to a file, closing a file, etc.
The followingtable shows some commonly used non-abstract classes in the
System.IO namespace:
FileStream Class
 FileStream class in System.IO namespace helps in reading from, writing to & closing files.
 You need to create a FileStream object to create a new file or open an existing file.
Syntax:
FileStream <object_name> = new FileStream( <file_name>,
<FileMode Enumerator>, <FileAccess Enumerator>, <FileShare Enumerator>);
Or
Dim <object_name> As FileStream = New FileStream(<file_name>, <FileMode
Enumerator>, <FileAccess Enumerator>, <FileShare Enumerator>)
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.

3. For example, for creating a FileStream object F for reading a file named sample.txt:
FileStream F = new FileStream("sample.txt", FileMode.Open, FileAccess.Read,
FileShare.Read);
Or
Dim f1 As FileStream = New FileStream("test.dat", FileMode.OpenOrCreate,
FileAccess.ReadWrite)
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

4. Example 1:- Program to create a new file in the D Drive:-
C#.net
static void Main(){
FileStream fs = new FileStream("d:createfileusingC#.txt", FileMode.Append,
FileAccess.Write);// String path = ("D:test1.txt");
StreamWriter sw = new StreamWriter(fs);
Console.WriteLine("File Created");
Console.WriteLine("Enter the text which you want to write to the file");
string str = Console.ReadLine();
VB.net
Sub Main()
Dim s As System.IO.Stream
s = System.IO.File.Open("d: createfileusingvb.txt", System.IO.FileMode.Create)
Console.WriteLine("File Created")
Console.ReadLine()
s.Close()
End Sub
}
Example2:- Programto Write data into a File
VB.net
Sub Main()
Dim s As System.IO.Stream
s = System.IO.File.Open("d:createusingvb.txt", System.IO.FileMode.Open,
System.IO.FileAccess.Write)
Dim I As Integer
For I = 0 To 10
s.WriteByte(CByte(I))
Next
Console.WriteLine("Data Entered")
s.Close()
Console.ReadLine()
Example3:Programto Readdata from a File
C# .net
static void Main(string[] args)
{
String path = @"D: createusingvb.txt ";//"d: createusingvb.txt",
String[] lines;
lines = File.ReadAllLines(path);
Console.WriteLine(lines[0]);
// Console.WriteLine(lines[1]);
Console.ReadKey();} }
VB.net
Sub Main()
Dim s As System.IO.Stream
s = System.IO.File.Open("d: createusingvb.txt", System.IO.FileMode.Open,
System.IO.FileAccess.Read)
Dim I As Integer
For I = 0 To 10
Console.WriteLine("{0}", s.ReadByte())
Next
Console.WriteLine("Data Ended")
s.Close()

5. Console.ReadLine() End Sub
Example 4 program to copy file
C#.net
static void Main(){
String path = @"D: createfileusingC#.txt"; // ("D:wow.txt");
String copypath = @"D:copyofcreatefileusingC#.txt";
Console.WriteLine("Coped");
File.Copy(path, copypath);
Console.ReadKey();}}
Example 5 Program to Delete a File
C#.net
static void Main()
{
String path = ("D: createfileusingC#.txt");//String path = @"D:test1.txt";
Console.WriteLine("The file is deleted");
File.Delete(path);
Console.ReadKey();
}
VB.net
Sub Main()
System.IO.File.Delete("d: createfileusingC#.txt")
Console.WriteLine("File deleted")
Console.ReadLine()
End Sub