Can I use .NET 4.0 API calls on .NET 2.0?

Question

If I make .NET 4.0 API calls and the customer only has .NET 2.0 installed, will my EXE work? I assume no -- absolutely not. But I want to reconfirm and point this out to my client yes/no.

Background... I'm from the Linux/PHP world. My client uses a Windows C# app on the frontend, and Linux/PHP on the backend. He's asked me to investigate this issue.

Answer 1

尝试运行使用.NET 4.0编写和编译的任何内容时，.NET 2.0运行时都会出错，但事实并非如此。

Answer 2

Application code targeted against the .NET 4.0 framework will not run in an environment that only has the .NET 2.0 framework installed.

See "Version Compatibility" section here: http://msdn.microsoft.com/en-us/library/8477k21c.aspx

Answer 3

What you can do is have your .NET 2 code access the .NET 4 libraries via a web service. If you were to expose the .NET 4 API via a web service, it would be agnostic of the .NET version and the technology between them all together.