preprocessor directive in nuget library

Question

I don't really understand those preprocessor directives what I have to write. I'm developing a library that should work for many frameworks eg .net framework 4.5, 4.6,... and for my application that runs with framework .NETStandard Version 1.5 -> so I guess this is dnxcore50 ?

public class MyClass
{
#if DOTNET5_4
    // do nothing
#else
    public void MyMethod()
    {
        Console.WriteLine("framework is supported");
        // and do anything with libraries available in the framework :)
    }
#endif
}

so this is what I got for now, but MyMethod is not available with any other framework. Using #if DOTNETCORE50 doesn't work, too.

I also tried to define constraints but my project fails to load when I try this.

Any idea what's the right solution?

Answer 1

There's no need to define them in project/solution-file anymore.

So, I just post an answer matching the current state (a few are still missing like net47 and so on, but you know what I mean):

#if (NET45 || NET451 || NET46 || NET461)
#define NetFramework
#endif

#if (NETSTANDARD1_0 || NETSTANDARD2_0 || NETSTANDARD1_5 || NETSTANDARD1_3 || NETSTANDARD1_6 || NETCOREAPP1_0 || NETCOREAPP1_1 || NETCOREAPP2_0)
#define NetCore
#endif

in what way they are now compatible or redundant, I dont' know. But this is the current names I know.

then you can

public class MyClass
{

#if NetFramework
    public void MyMethod()
    {
        Console.WriteLine("framework is supported");
        // and do anything with libraries available in the framework :)
    }
#endif

}