How to get the version of the .NET Framework being targeted? [duplicate]

Question

How can i get the version of the .NET Framework i am targeting, rather than the version of the .NET framework the app is currently running under?

For example, if the application targets .NET Framework 4.5, i would need to know that i am targeting .NET Framework 4.5.

For example, checking System.Environment.Version:

• when targeting .NET Framework 4: 4.0.30319.18502
• when targeting .NET Framework 4.5: 4.0.30319.18502

So that doesn't work.

The real goal is to try to work around the lack of compiler defines in .NET.

Answer 1

That's simple - check the TargetFrameworkAttribute:

var targetFrameworkAttribute = Assembly.GetExecutingAssembly()
    .GetCustomAttributes(typeof(System.Runtime.Versioning.TargetFrameworkAttribute), false)
    .SingleOrDefault();

Answer 2

What prevents you from using an ordinary /define?

csc /define:NET45 /optimize /out:MyProgram.exe *.cs

with

using System;
public class Test 
{
    public static void Main() 
    {
        #if (NET45) 
            Console.WriteLine("NET45 targeted");
        #else
            Console.WriteLine("NET45 not targeted");
        #endif
    }
}