Conditional per TargetFramework in MsBuild 15

问题

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>

回答1:

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

.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 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 Core 1.0        --> NETCOREAPP1_0
.Net Core 1.1        --> NETCOREAPP1_1
.Net Core 2.0        --> NETCOREAPP2_0
.Net Core 2.1        --> NETCOREAPP2_1

For example:

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

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

来源：https://stackoverflow.com/questions/42754123/conditional-per-targetframework-in-msbuild-15