Conditional per TargetFramework in MsBuild 15

Question

With the new MsBuild version it's really easy to target multiple frameworks and framework versions in .csproj project:

<TargetFrameworks>net40;net45;net461;netcoreapp1.1</TargetFrameworks>

Now, how do I get a constant defined for each of them so that I can have certain code only be part of e.g. netcoreapp1.1 pass and not full framework compilation?

I'd like to be able to add a preprocessor directive like this one:

#if NET_CORE
    // some code
#endif

And the same for full .NET Framework and possibly .NET Standard.

The other questions I found don't take new <TargetFrameworks> way of defining the framework into accounts. Stuff like this doesn't work:

<DefineConstants Condition=" '$(TargetFramework)' == '.NETCoreApp' ">NET_CORE</DefineConstants>

Answer 1

There are already various preprocessor symbols defined that you can use. From the docs:

.NET Framework

Framework/Version	Symbol
.NET Framework (any version)	NETFRAMEWORK
.NET Framework 2.0	NET20
.NET Framework 3.5	NET35
.NET Framework 4.0	NET40
.NET Framework 4.5	NET45
.NET Framework 4.5.1	NET451
.NET Framework 4.5.2	NET452
.NET Framework 4.6	NET46
.NET Framework 4.6.1	NET461
.NET Framework 4.6.2	NET462
.NET Framework 4.7	NET47
.NET Framework 4.7.1	NET471
.NET Framework 4.7.2	NET472
.NET Framework 4.8	NET48

.NET Standard

Framework/Version	Symbol
.NET Standard (any version)	NETSTANDARD
.NET Standard 1.0	NETSTANDARD1_0
.NET Standard 1.1	NETSTANDARD1_1
.NET Standard 1.2	NETSTANDARD1_2
.NET Standard 1.3	NETSTANDARD1_3
.NET Standard 1.4	NETSTANDARD1_4
.NET Standard 1.5	NETSTANDARD1_5
.NET Standard 1.6	NETSTANDARD1_6
.NET Standard 2.0	NETSTANDARD2_0
.NET Standard 2.1	NETSTANDARD2_1

.NET Core

Framework/Version	Symbol
.NET [Core] (any version)	NETCOREAPP
.NET Core 1.0	NETCOREAPP1_0
.NET Core 1.1	NETCOREAPP1_1
.NET Core 2.0	NETCOREAPP2_0
.NET Core 2.1	NETCOREAPP2_1
.NET Core 2.2	NETCOREAPP2_2
.NET Core 3.0	NETCOREAPP3_0
.NET Core 3.1	NETCOREAPP3_1

.NET 5+

Framework/Version	Symbol
.NET 5.0	NET5_0

Additional <framework>_OR_GREATER Symbols

From the release of .NET6, a suite of <framework>_OR_GREATER symbols were added:

For example:

Target Framework	Symbols
.NET Framework	NET48_OR_GREATER, NET472_OR_GREATER, NET471_OR_GREATER, NET47_OR_GREATER, NET462_OR_GREATER, NET461_OR_GREATER, NET46_OR_GREATER, NET452_OR_GREATER, NET451_OR_GREATER, NET45_OR_GREATER, NET40_OR_GREATER, NET35_OR_GREATER, NET20_OR_GREATER
.NET Standard	NETSTANDARD2_1_OR_GREATER, NETSTANDARD2_0_OR_GREATER, NETSTANDARD1_6_OR_GREATER, NETSTANDARD1_5_OR_GREATER, NETSTANDARD1_4_OR_GREATER, NETSTANDARD1_3_OR_GREATER, NETSTANDARD1_2_OR_GREATER, NETSTANDARD1_1_OR_GREATER, NETSTANDARD1_0_OR_GREATER
.NET 5+ (and .NET Core)	NET6_0_OR_GREATER, NET6_0_ANDROID_OR_GREATER, NET6_0_IOS_OR_GREATER, NET6_0_MACOS_OR_GREATER, NET6_0_MACCATALYST_OR_GREATER, NET6_0_TVOS_OR_GREATER, NET6_0_WINDOWS_OR_GREATER, NET5_0_OR_GREATER, NETCOREAPP_OR_GREATER, NETCOREAPP3_1_OR_GREATER, NETCOREAPP3_0_OR_GREATER, NETCOREAPP2_2_OR_GREATER, NETCOREAPP2_1_OR_GREATER, NETCOREAPP2_0_OR_GREATER, NETCOREAPP1_1_OR_GREATER, NETCOREAPP1_0_OR_GREATER

#if NETSTANDARD1_6
    Console.WriteLine("This is .Net Standard 1.6");
#endif

#if NETCOREAPP2_0
    Console.WriteLine("This is .Net Core 2.0");
#endif