Why is .NET framework not cross-platform?

Yes, C# is fully cross-platform thanks to . NET Core. . NET Core is a free and open-source, managed computer software framework for Windows, Linux, and macOS operating systems.

The main problem is that the implementations can differ from each other, making it hard to run an application on multiple machines out of the box . Source code shouldn’t have to be altered, if not some of the libraries are not ported to mono, or different libraries are used.11 Kas 2011

NET Core is cross-platform . It runs on Windows, OS X and multiple distributions of Linux. It also supports different CPU architectures.

. NET Multi-platform App UI (. NET MAUI) is a cross-platform framework for creating native mobile and desktop apps with C# and XAML. … NET MAUI, you can develop apps that can run on Android, iOS, macOS, and Windows from a single shared code-base.