Overview of Types for Files/Directories

File & Directory IO

All methods return void unless otherwise specified.

Files

Goal	Use
Check for a file	`File.Exists` (returns `bool`)
Copy a file	`File.Copy` `FileInfo.CopyTo` (returns `FileInfo`)
Delete a file	`File.Delete`, `FileInfo.Delete`
Move/rename a file	`File.Move`, `FileInfo.MoveTo`
Retrieve a full path	`Path.GetFullPath`
Retrieve file name and extension	`Path.GetFileName`
Retrieve a file extension	`Path.GetExtension`
Change a file extension	`Path.ChangeExtension`

Text Files

Goal	Use
Create a text file	`File.CreateText` (returns `StreamWriter`) `File.Create` (returns `FileStream`) `FileInfo.CreateText` (returns `StreamWriter`) `FileInfo.Create` (returns `FileStream`)
Write to a text file	`StreamWriter` (`Write{Async}`, `WriteLine{Async}`) File (`WriteAllLines{Async}`, `WriteAllText{Async}`)
Append to a text file	`File.AppendText` (returns `StreamWriter`) `FileInfo.AppendText` (returns `StreamWriter`)
Read from a text file	`StreamReader`

Binary Files

Goal	Use
Read from	`BinaryReader`
Write to	`BinaryWriter`

Directories

Goal	Use
Check for a directory	`Directory.Exists` (returns `bool`)
Create a directory	`Directory.CreateDirectory` (returns `DirectoryInfo`)
Create a subdirectory	`DirectoryInfo.CreateSubdirectory` (returns `DirectoryInfo`)
Copy a directory	Directories are copied by creating the directory in the new destination and then copying files to it
Delete a directory	`Directory.Delete`, `DirectoryInfo.Delete`
Move/rename a directory	`Directory.Move`, `DirectoryInfo.MoveTo`

Enumerating Files and Directories [ Documentation]

Enumerable collections provide superior performance vs arrays when working with large collections. The Directory and DirectoryInfo classes have enumeration methods that return enumerable collections:

To retrieve	Use
Directory names	`Directory.EnumerateDirectories`
DirectoryInfo objects	`DirectoryInfo.EnumerateDirectories`
File names	`Directory.EnumerateFiles`
FileInfo objects	`DirectoryInfo.EnumerateFiles`
Directory and file names	`Directory.EnumerateFileSystemEntries`
FileSystemInfo objects	`DirectoryInfo.EnumerateFileSystemInfos`

Compression and Decompression

For all examples:

using System.IO.Compression;

Compression and Decompression For zip files

Compression (Creating a zip file):

var startPath = "/source/directory";
var zipFilePath = "/destination/compressed.zip";
zipFile.CreateFromDirectory(startPath, zipFilePath);)

Decompression (Extracting Contents of a zip file):

var zipFilePath = "/destination/compressed.zip";
var destinationPath = "/destination/directory";

// Normalize the destination path:
destinationPath = Path.GetFullPath(destinationPath);

// If the destinationPath does not end with the directory separator character, a path traversal attack is possible:
if (!destinationPath.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal))
    destinationPath += Path.DirectorySeparatorChar;

zipFile.ExtractToDirectory(zipFilePath, destinationPath);

Adding to a zip file

var zipFilePath = "/destination/compressed.zip";

using FileStream zipFilePath = new FileStream(zipFilePath, FileMode.Open);

using ZipArchive archive = new ZipArchive(zipFilePath, ZipArchiveMode.Update);
var fileEntry = archive.CreateEntry("SomeFile.txt");

using StreamWriter writer = new StreamWriter(fileEntry.Open());
writer.WriteLine("Some text...");

Compression and Decompression for GZip

Compression:

var fileToCompress = new FileInfo("/source/file.txt");
using FileStream originalFileStream = fileToCompress.OpenRead();
using FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".gz");
using GZipStream compressionStream = new GZipStream(compressedFileStream, CompressionMode.Compress);
originalFileStream.CopyTo(compressionStream);

Decompression:

var fileToDecompress = new FileInfo("/source/compressed.gz");
using FileStream originalFileStream = fileToDecompress.OpenRead();
using FileStream decompressedFileStream = File.Create("/destination/decompressed.txt");
using GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress);
decompressionStream.CopyTo(decompressedFileStream);