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Base Class Library (BCL)

Short Introduction​

The Base Class Library provides fundamental functionality for .NET applications, including basic data types, file I/O, collections, and more.

Official Definition​

The Base Class Library (BCL) is a standard library that provides basic functionality for .NET applications, including primitive data types, collections, file I/O, string manipulation, and other essential functionality.

Usage​

// Common BCL usage examples
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;

// Collections
var list = new List<string> { "item1", "item2" };
var dictionary = new Dictionary<string, int> { ["key1"] = 1 };

// File I/O
await File.WriteAllTextAsync("file.txt", "Hello World");
string content = await File.ReadAllTextAsync("file.txt");

// DateTime
DateTime now = DateTime.UtcNow;
DateOnly today = DateOnly.FromDateTime(now);

// String manipulation
string text = "Hello World";
string upper = text.ToUpper();
string[] parts = text.Split(' ');

Use Cases​

  • Basic application functionality
  • Data manipulation
  • File operations
  • Network operations
  • Threading and async operations