.NET Framework
.NET Framework is a proprietary software framework developed by Microsoft that runs primarily on Windows. It provides a large class library called Framework Class Library (FCL) and language interoperability across several programming languages, enabling developers to build a wide range of applications, including desktop, web, and mobile. It includes features such as memory management, security, and exception handling, and supports languages like C#, VB.NET, and F#.
Developers should learn .NET Framework for building Windows-specific applications, particularly enterprise-level desktop software, legacy web applications using ASP.NET Web Forms, and services that integrate deeply with Microsoft technologies like Active Directory or SQL Server. It is essential for maintaining and extending existing systems in corporate environments where Windows is the dominant platform, and it offers robust tools for large-scale, mission-critical applications.