Free C# Source Code
The free C# source code is available for this implementation of the Microsoft XNA 4 Framework, including libraries of wrappers for for 3d graphics audio or compute functionality (OpenGL, OpenCL and OpenAL). There is also an open-source wrapper for the DirectX API under the .NET platform, and a networking library for the .NET Framework with a client/server API.
Visual Studio samples
These C# source code examples can be downloaded or browsed online, and include everything from a simple calendar to code samples and applications for Windows 8, Windows Phone, Windows Azure, Office, SharePoint, Silverlight and other products.
sourcecodester.com free c# projects with source code
Free c# projects with source code. Examples include inventory management, calendars, chat and games.
101 Visual Basic and C# Code Samples
This download includes a master set of Visual Basic and Visual C# code samples demonstrating various aspects of the language in the following areas: syntax, data access, Windows Forms, Web development and Web services, XML, security, the .NET Framework, file system and file I/O, interop and migration issues, COM+, ADO.NET, and advanced topics including graphics with GDI+, remoting, serialization, MSMQ, and Windows services.
Q42 Multiplayer engine
Chess Game Starer Kit
A free source code Visual Studio C# program for building chess programs, which includes a graphical representation of the chessboard and only allows for valid moves.
Windows C# port of the SQLite library released under an MIT license.
Data Structures and Algorithms with Object-Oriented Design Patterns in C#
The source for the book can be downloaded.
Airplane war is intended to be a 3d world war I airplane simulator in c# and using directx 9. Source code and binaries are available.
The Advanced C#/.NET Tutorial
Advanced C# tutorials with sample source code that can be downloaded.