How to set .NET Core in #if statement for compilation

Question

I created a multi-targeted framework project. I use something like this:

  #if NET40     Console.WriteLine("Hello from .NET Core 4");   #endif 

But I can't find a wildcard for .NET Core. I tried:

   #if NETCOREAPP1.0      Console.WriteLine("Hello from .NET Core");    #endif 

But it is not valid statement.

Answer 1

You need an underscore, _, instead of a point:

NETCOREAPP1_0 or the more recent NETCOREAPP1_1 and NETCOREAPP2_0

The documentation for Target frameworks in SDK-style projects includes a list for the different preprocessor symbols.

.NET Framework

NETFRAMEWORK, NET48, NET472, NET471, NET47, NET462, NET461, NET46, NET452, NET451, NET45, NET40, NET35, NET20

.NET Standard

NETSTANDARD, NETSTANDARD2_1, NETSTANDARD2_0, NETSTANDARD1_6, NETSTANDARD1_5, NETSTANDARD1_4, NETSTANDARD1_3, NETSTANDARD1_2, NETSTANDARD1_1, NETSTANDARD1_0

.NET 5+ and .NET Core

NET, NET6_0, NET6_0_ANDROID, NET6_0_IOS, NET6_0_MACOS, NET6_0_MACCATALYST, NET6_0_TVOS, NET6_0_WINDOWS, NET5_0, NETCOREAPP, NETCOREAPP3_1, NETCOREAPP3_0, NETCOREAPP2_2, NETCOREAPP2_1, NETCOREAPP2_0, NETCOREAPP1_1, NETCOREAPP1_0

Mono

For Mono you can usually use the NetFramework monikers known by your version of Mono. For instance, Mono 6.12 includes all NetFramework versions from 2.0 to 4.8. But if you must recognise Mono per se, then MONO and __MonoCS__ should both be defined.

Answer 2

Extension of Devon's answer for Visual Studio 2017 .csproj files:

Looking at the table here, you can easily define constants by using regular expressions. So you don't need to think about updating the conditions if target frameworks are added/changed.

<PropertyGroup Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('$(TargetFramework)', '^net\d'))">   <DefineConstants>NETFRAMEWORK</DefineConstants> </PropertyGroup> <PropertyGroup Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('$(TargetFramework)', '^netstandard\d'))">   <DefineConstants>NETSTANDARD</DefineConstants> </PropertyGroup> <PropertyGroup Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('$(TargetFramework)', '^netcoreapp\d'))">   <DefineConstants>NETCORE</DefineConstants> </PropertyGroup> 

Usage:

#if NETFRAMEWORK     FrameworkSpecific(); #endif  #if NETSTANDARD     StandardSpecific(); #endif  #if NETCORE     CoreSpecific(); #endif