Directory.build.targets

<Project>
  <PropertyGroup Condition="$(TargetFramework.StartsWith('netstandard'))">
    <DefineConstants>$(DefineConstants);NETSTANDARD;PORTABLE</DefineConstants>
  </PropertyGroup>
  <PropertyGroup Condition="$(TargetFramework.StartsWith('net4'))">
    <DefineConstants>$(DefineConstants);NET_471;XAML</DefineConstants>
  </PropertyGroup>
  <PropertyGroup Condition="$(TargetFramework.StartsWith('uap'))">
    <DefineConstants>$(DefineConstants);NETFX_CORE;XAML;WINDOWS;WINDOWS_UWP</DefineConstants>
    <TargetPlatformVersion>10.0.16299.0</TargetPlatformVersion>
    <TargetPlatformMinVersion>10.0.16299.0</TargetPlatformMinVersion>
  </PropertyGroup>
  <PropertyGroup Condition="$(TargetFramework.StartsWith('Xamarin.iOS'))">
    <DefineConstants>$(DefineConstants);MONO;UIKIT;COCOA;IOS</DefineConstants>
  </PropertyGroup>
   <PropertyGroup Condition="$(TargetFramework.StartsWith('Xamarin.Mac'))">
    <DefineConstants>$(DefineConstants);MONO;COCOA;MAC</DefineConstants>
  </PropertyGroup>
  <PropertyGroup Condition="$(TargetFramework.StartsWith('MonoAndroid'))">
    <DefineConstants>$(DefineConstants);MONO;ANDROID</DefineConstants>
    <MonoAndroidResourcePrefix>Resources</MonoAndroidResourcePrefix>
    <AndroidResgenClass>Resource</AndroidResgenClass>
    <AndroidResgenFile>Resources\Resource.designer.cs</AndroidResgenFile>
  </PropertyGroup>
  <PropertyGroup Condition="$(TargetFramework.StartsWith('netcoreapp'))">
    <DefineConstants>$(DefineConstants);NETCOREAPP</DefineConstants>
  </PropertyGroup>
</Project>