Manipulating Files in .NET | C# Cheat Sheet¶

Enumerating Directories¶

List All Directories¶

To list all directories in a given folder:

IEnumerable<string> listOfDirectories = Directory.EnumerateDirectories("dir");

foreach (var dir in listOfDirectories) {
    Console.WriteLine(dir);
}

List All Files in a Directory¶

To list all files within a specific directory:

IEnumerable<string> files = Directory.EnumerateFiles("dir");

foreach (var file in files) {
    Console.WriteLine(file);
}

Recursively Enumerate Files in All Subdirectories¶

To search through a directory and its subdirectories for specific files:

IEnumerable<string> allFilesInAllFolders = Directory.EnumerateFiles("dir", "*.txt", SearchOption.AllDirectories);

foreach (var file in allFilesInAllFolders) {
    Console.WriteLine(file);
}

Working with Directories¶

Get Current Directory¶

To get the path of the current working directory:

Console.WriteLine(Directory.GetCurrentDirectory());

Accessing Special Folders¶

To retrieve paths to special system folders in a cross-platform way:

Console.WriteLine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments));

Creating Directories¶

To create a directory and any necessary subdirectories:

Directory.CreateDirectory(Path.Combine(Directory.GetCurrentDirectory(), "dir", "subDir", "newDir"));

Check If Directory Exists¶

To check if a specific directory exists:

Console.WriteLine(Directory.Exists("dir")); // outputs: "true"

Working with File Paths¶

Combining Paths¶

To correctly combine multiple path segments:

Console.WriteLine(Path.Combine("dir", "subDir")); // outputs: dir/subDir

Get File Extension¶

To retrieve the file extension of a given filename:

Console.WriteLine(Path.GetExtension("greeting.txt")); // outputs: .txt

Reading and Writing Files¶

Reading a File¶

To read all text from a file:

Console.WriteLine(File.ReadAllText("greeting.txt"));

Writing to a File¶

To create or overwrite a file with specified content:

File.WriteAllText("greeting.txt", "Hello World Kim!");

Appending to a File¶

To append data to an existing file, or create it if it doesn’t exist:

File.AppendAllText("greeting.txt", $"Hello World Lucas!{Environment.NewLine}");

Working with File Information¶

Getting File Info¶

To get detailed information about a file:

FileInfo info = new FileInfo("greeting.txt");

Console.WriteLine($"Full Name: {info.FullName}");
Console.WriteLine($"Directory: {info.Directory}");
Console.WriteLine($"Extension: {info.Extension}");
Console.WriteLine($"Create Date: {info.CreationTime}");