Currently studying a Computer Science Degree, in Programming we are using C# in Visual Studio. So need a replacement that can run work already started in Visual.
Thanks in advance.
Xamarin, a developer for Mono, created MonoDevelop, which is an IDE for C# on Ubuntu. As far as I know, it can open VS projects. You can find it within the Synaptic Package Manager or Ubuntu Software Center. Here is the homepage. Any other questions about it can most likely be answered by their FAQ.
For Linux and Mac, Visual Studio Code(VS Code) is the best alternative of Visual Studio. It is great code editor for Node.js and C# developers. You can also use it for other languages too. Also Visual Studio Code is an open source software. Its source code is on GitHub.
Another alternative is Mono, which is an open source implementation of Microsoft's .NET Framework based on the ECMA standards for C# and the Common Language Runtime. Mono is sponsored by Microsoft. MonoDevelop is the official IDE of Mono. You can also use MonoDevelop for F# and other languages too.