The .NET Framework is not specific to any programming language. Programming languages from Microsoft, like c#, vb.net, visual-c++ CLI, and f#, as well as many other languages from other vendors, all use the same .NET Framework.
The .NET Framework includes a large library of functions as part of the Base Class Library (BCL), including those related to user interface design, data access, database connectivity, cryptography, development of web applications, mathematical algorithms, and network communications. This extensive library simplifies development and makes it easy to rapidly develop new applications.
As such, questions like "How do I do file I/O in C#?" should really be "How do I do file I/O with .NET?". Because such a question concerns the file I/O libraries provided by the .NET Framework, it should be tagged with both the .net tag, and with the c# tag, to indicate that you'd like the answer to be written in the C# programming language.
See also: mono, .net-core (do NOT use the .net tag for questions about .NET Core).
- What are some useful online resources for .NET developers?
- What podcasts are there that cover .NET?
- .NET Framework Wikipedia Link
- .NET documentation site
Versions of .NET
- .net-1.0 .NET Framework 1.0 - CLR 1.0 - 2002-02-13
- .net-1.1 - .NET Framework 1.1 - CLR 1.1 - 2003-04-24
- .net-2.0 - .NET Framework 2.0 - CLR 2.0 - 2005-11-07
- .net-3.0 - .NET Framework 3.0 - CLR 2.0 - 2006-11-06
- .net-3.5 - .NET Framework 3.5 - CLR 2.0 - 2007-11-19
- .net-4.0 - .NET Framework 4.0 - CLR 4 - 2010-04-12
- .net-4.5 - .NET Framework 4.5 - CLR 4 - 2012-08-15
- .net-4.5.1 - .NET Framework 4.5.1 - CLR 4 - 2013-10-17
- .net-4.5.2 - .NET Framework 4.5.2 - CLR 4 - 2014-05-05
- .net-4.6 - .NET Framework 4.6 - CLR 4 - 2015-07-20
- .net-4.6.1 - .NET Framework 4.6.1 - CLR 4 - 2015-11-30
- .net-4.6.2 - .NET Framework 4.6.2 - CLR 4 - 2016-08-02
- .net-4.7 - .NET Framework 4.7 - CLR 4 - 2017-04-05
- .net-4.7.1 - .NET Framework 4.7.1 - CLR 4 2017-10-17
- .net-4.7.2 - .NET Framework 4.7.2 - CLR 4 2018-02-05
- .net-4.8 - .NET Framework 4.8 - CLR 4 2019-04-18
Latest stable release
- How can I measure performance of my .NET applications?
- How to monitor .NET Application Performance?
- What are some common profilers used in .NET?
- Fundamentals of Garbage Collection.
- How does the .NET Garbage Collector work?
- When should I use GC.SuppressFinalize()?
- When does the .NET Garbage Collector suspend all threads?
Free .NET Programming Books (C# / F# / VB / Nemerle / Visual Studio)
- C# Essentials
- C# Programming - Wikibook
- C# Yellow Book (intro to programming)
- Charles Petzold's .NET Book Zero
- Data Structures and Algorithms with Object-Oriented Design Patterns in C#
- Entity Framework
- Moving to Microsoft Visual Studio 2010
- Programming in F# 3.0
- Programmer's Heaven C# School Book (covers C# 1.0 and 2.0)
- Threading in C#
- Visual Basic Essentials
- Visual Studio Tips and Tricks (VS 2003-2005 only)
- Foundations Of Programming
- BrightstarDb - BrightstarDB is a native .NET RDF triple store
- LiteDB - A .NET NoSQL Document Store in a single data file - http://www.litedb.org
- RavenDB - A LINQ-enabled document database for .NET
- Marten - PostgreSQL as a document database and event store for .NET applications
- Realm Xamarin - A fast, easy-to-use alternative to SQLite & ORMs - https://realm.io/docs/dotnet/latest/
- Streamstone - Event store for Azure Table Storage
- Ignite - Distributed in-memory platform: document database with SQL and LINQ support; distributed computations; distributed services and events.
- Yessql - A .NET document database working on any RDBMS
- JsonFlatFileDataStore - Simple JSON flat file data store with support for typed and dynamic data
- MySQL Connector - Connector/Net is a fully-managed ADO.NET driver for MySQL
- Npgsql - .NET data provider for PostgreSQL
- MongoDB - Official MongoDB C# driver
- RethinkDb.Driver - A RethinkDB database driver in C# striving for 100% ReQL API compatibility and completeness.
- ServiceStack Redis - .NET's leading C# Redis client
- StackExchange Redis - General purpose Redis client from Stack Exchange
- Cassandra - DataStax .NET driver for Apache Cassandra
- Couchbase - Official Couchbase .NET client library, based on the Enyim Memcached client
- Firebird.NET - The .NET Data provider is written in C# and provides a high-performance, native implementation of the Firebird API
Useful .NET Libraries
- Math.NET Numerics - special functions, linear algebra, probability models, random numbers, interpolation, integral transforms and more
Package managers for external libraries
- NuGet (formerly known as NuPack) - Microsoft (developer-focused package management system for the .NET platform intent on simplifying the process of incorporating third-party libraries into a .NET application during development)
- OpenWrap - Sebastien Lambla - Open Source Dependency Manager for .NET applications
- Prebuild - Generate project files for all Visual Studio versions, including major IDEs and tools like SharpDevelop, MonoDevelop, NAnt and Autotools
Dependency Injection/Inversion of Control
- Unity Framework - Microsoft
- StructureMap - Jeremy Miller
- Castle Windsor
- Spring Framework
- Simple Injector
- Managed Extensibility Framework
- Logging Application Block - Microsoft
- Log4Net - Apache
- Error Logging Modules and Handlers (ELMAH)
- Logging Abstraction API "Common.Logging"
Design by Contract
- SevenZipSharp to pack, unpack a lot of different packages (including RAR, 7-Zip, etc.).
- ZipStorer A Pure C# Class to Store Files in the ZIP format
- Ajax Control Toolkit - Microsoft
- AJAXNet Pro
- ASP.NET MVC Project Awesome - Ajax helpers for ASP.NET MVC
- Data accessors from the Data Access Application Block
- Entity Framework - Microsoft
- NHibernate and FluentNHibernate
- Castle ActiveRecord
- Truss Data binding and real time property synchronisation library
- Microsoft Chart Controls for ASP.NET 3.5 SP1
- Microsoft Chart Controls for Windows Forms
- ZedGraph Charting
- NPlot - Charting for ASP.NET and Windows Forms
- ImageResizer - URL-driven image processing for both ASP.NET and .NET
Automated Web Testing
Misc Testing/Quality Support/Behavior Driven Development (BDD)
- Glimpse - Firebug for your webserver
MS Word/Excel Documents Manipulation
- DocX to create, read, manipulate formatted word documents. Easy syntax, working nicely, actively developed. No Microsoft Office necessary.
- Excel XML Writer allows creation of .XLS (Excel) files. No Microsoft Office necessary. It has been a while since it has been updated. It also provides a code generator to create code from already created XLS file (saved as XML). Haven't tested this but looks very promising. The author hasn't updated this in awhile.
- Excel Reader allows creation/reading of .XLS (Excel) files. No Microsoft Office necessary. It has been awhile since it has been updated.
- Excel Package allows creation/reading of .XLSX (Excel 2007) files. No Microsoft Office necessary. The author is gone, so it's out of date.
- EPPlus is based on Excel Package and allows creation/reading of .XLSX (Excel 2007). It is actually the most advanced even comparing to NPOI.
- NPOI is the .NET version of POI Java project at https://poi.apache.org/. POI is an open source project which can help you read/write Excel, Word, and PowerPoint files. Latest sources available at GitHub repository
- LINQ to Twitter - LINQ-based wrapper for all Twitter API functionality in C#
- Facebook C# SDK - A toolkit for creating Facebook applications / integrating websites with Facebook using the new Graph API or the old rest API.
- sharpSerializer - XML/binary serializer for WPF, ASP.NET AND Silverlight
- protobuf-net - .NET implementation of Google's cross-platform binary serializer (for all .NET platforms)
Chat about .NET with other Stack Overflow users
RESTFul Web Services
- RestSharp - Simple REST and HTTP API Client for .NET
- CSLA Framework - Business Objects Framework
- Prism - Composite UI application block for WPF, Silverlight and Windows Phone 7 - Microsoft patterns & practices
- Enterprise Library 5.0 - Logging, Exception Management, Caching, Cryptography, Data Access, Validation, Security, Policy Injection - Microsoft patterns & practices
- File helpers library
- C5 Collections - Collections for .NET
- Quartz.NET - Enterprise Job Scheduler for .NET Platform
- MiscUtil - Utilities by Jon Skeet
- Noda Time - DateTime replacement (idiomatic port of Joda Time from Java)
- Lucene.net - Text indexing and searching
- Json.NET - LINQ over JSON
- Flee - expression evaluator
- PostSharp - AOP
- IKVM - brings the extensive world of Java libraries to .NET.
- C# Webserver - Embeddable webserver
- Long Path - Microsoft
- .NET Engines for the GOLD Parsing System
- Smart Thread Pool - Thread Pool management library
- NCQRS - library for event-driven architectures (CQRS).
- NBug - Automated exception and error reporting tool (can generate minidumps)
- Splicer.Net - library for the .NET Framework that aims to simplify developing applications for editing and encoding audio and video using DirectShow.
- Pex - a tool for automatic test case generation
- Lidgren Network - a networking library for .NET Framework which uses a single UDP socket to deliver a simple API for connecting a client to a server, reading and sending messages.
- LINQPad - Scripting IDE for C# / VB / SQL with emphasis on LINQ to databases