Curriculum
File Handling in C# is an essential skill for every .NET developer. File Handling in C# allows applications to create, read, write, update, copy, move, and delete files and directories. Whether you are building an ASP.NET Core Application, Desktop Application, Web API, Hospital Management System, Banking Application, ERP Software, CRM System, or Enterprise Software Solution, File Handling in C# is frequently used for storing logs, reports, configuration files, user data, backups, and document management.
Understanding File Handling in C# is important because most real-world applications interact with files stored on local machines, servers, cloud storage, and network drives.
File Handling in C# refers to the process of working with files and directories using the .NET Framework’s System.IO namespace.
The System.IO namespace provides classes for:
Namespace:
using System.IO;Most file-related operations are performed through this namespace.
File Handling in C# helps developers:
File management is an important part of enterprise software development.
A file contains data.
Examples:
StudentReport.txt
Employees.csv
Config.json
Invoice.pdfA directory (folder) organizes files.
Examples:
Students
Reports
Invoices
DocumentsApplications often work with both files and directories.
The File class provides static methods for file operations.
Common methods:
Create
WriteAllText
ReadAllText
Copy
Move
Delete
ExistsThese methods simplify file management.
Example:
File.Create(
@"C:\Files\Test.txt");Output:
File CreatedA new file is created at the specified location.
Example:
bool exists =
File.Exists(
@"C:\Files\Test.txt");
Console.WriteLine(
exists);Output:
TrueThis helps prevent runtime errors.
Example:
File.WriteAllText(
@"C:\Files\Test.txt",
"Welcome to C# File Handling");Output:
Content WrittenThe file content is replaced with new data.
Example:
string content =
File.ReadAllText(
@"C:\Files\Test.txt");
Console.WriteLine(
content);Output:
Welcome to C# File HandlingThis is one of the most commonly used file operations.
Example:
File.AppendAllText(
@"C:\Files\Test.txt",
"\nLearning File Handling");Output:
Data AddedExisting content remains unchanged.
Example:
File.Copy(
@"C:\Files\Test.txt",
@"C:\Backup\Test.txt");Output:
File CopiedThis is useful for backup operations.
Example:
File.Move(
@"C:\Files\Test.txt",
@"C:\Archive\Test.txt");Output:
File MovedThe file is transferred to a new location.
Example:
File.Delete(
@"C:\Files\Test.txt");Output:
File DeletedAlways verify file existence before deletion.
The Directory class helps manage folders.
Common methods:
CreateDirectory
Delete
Exists
Move
GetFiles
GetDirectoriesDirectory management is frequently required in enterprise applications.
Example:
Directory.CreateDirectory(
@"C:\Reports");Output:
Folder CreatedThe folder is created if it does not already exist.
Example:
bool exists =
Directory.Exists(
@"C:\Reports");Output:
TrueThis helps avoid exceptions.
Example:
string[] files =
Directory.GetFiles(
@"C:\Reports");Output:
List of FilesUseful for report processing systems.
A stream represents a sequence of bytes flowing between a source and destination.
Examples:
File Streams
Network Streams
Memory StreamsStreams provide greater control over file operations.
StreamWriter writes data to files.
Example:
StreamWriter writer =
new StreamWriter(
@"C:\Files\Data.txt");
writer.WriteLine(
"Welcome to C#");
writer.Close();Output:
Data SavedStreamWriter is widely used in logging systems.
Example:
using(StreamWriter writer =
new StreamWriter(
@"C:\Files\Data.txt"))
{
writer.WriteLine(
"Hello World");
}The file automatically closes after use.
This is the preferred approach.
StreamReader reads file content.
Example:
StreamReader reader =
new StreamReader(
@"C:\Files\Data.txt");
string content =
reader.ReadToEnd();
reader.Close();Output:
Hello WorldStreamReader is commonly used for file processing.
Example:
using(StreamReader reader =
new StreamReader(
@"C:\Files\Data.txt"))
{
string content =
reader.ReadToEnd();
Console.WriteLine(
content);
}This ensures proper resource cleanup.
Example:
using(StreamReader reader =
new StreamReader(
@"C:\Files\Data.txt"))
{
string line;
while(
(line =
reader.ReadLine())
!= null)
{
Console.WriteLine(
line);
}
}Useful when processing large files.
FileInfo provides detailed information about files.
Example:
FileInfo file =
new FileInfo(
@"C:\Files\Data.txt");
Console.WriteLine(
file.Name);
Console.WriteLine(
file.Length);Output:
Data.txt
2048Useful for file management applications.
Example:
DirectoryInfo directory =
new DirectoryInfo(
@"C:\Files");Properties:
Name
CreationTime
Parent
RootProvides advanced folder management features.
Example:
using(StreamWriter writer =
new StreamWriter(
"log.txt", true))
{
writer.WriteLine(
DateTime.Now +
" User Logged In");
}Output:
Log Entry CreatedLogging systems heavily use file handling.
Example:
File.WriteAllText(
"StudentReport.txt",
"Student Name: Rahul");Output:
Report GeneratedEducational software frequently generates reports.
Example:
if(File.Exists(path))
{
}Ensures resources are released.
File operations can fail unexpectedly.
Example:
try
{
}
catch(IOException ex)
{
}Store paths in configuration files.
Prevent resource leaks.
Can lock files.
May crash applications.
Makes maintenance difficult.
May consume excessive memory.
Can result in data loss.
Transaction Reports
Audit Logs
Backup FilesInvoices
Product Reports
Sales LogsPatient Records
Medical Reports
PrescriptionsStudent Reports
Attendance Sheets
Result FilesFile Handling in C# is used extensively across industries.
File Handling in C# refers to creating, reading, writing, updating, and deleting files and directories.
System.IOStreamWriter writes data to files.
StreamReader reads data from files.
File provides static methods, while FileInfo provides object-oriented file management.
Most applications need to store, process, and manage persistent data.
File Handling in C# allows applications to work with files and directories.
The System.IO namespace.
StreamWriter is used to write data to files.
StreamReader is used to read file data.
FileInfo provides detailed information and operations for specific files.
It enables data storage, reporting, logging, backups, and document management in software applications.