Multi targets project build success on Windows but failed on travis-ci

I developed a project target on .netstandard1.6 and net45,I can build it successfully on my local windows and appveyor,but when I built via travis-ci,I met the error as follows:

/usr/share/dotnet/sdk/1.0.4/Microsoft.Common.CurrentVersion.targets(1111,5): error MSB3644: The reference assemblies for framework ".NETFramework,Version=v4.5" were not found. 

To resolve this, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framework for which you have the SDK or Targeting Pack installed. 

Note that assemblies will be resolved from the Global Assembly Cache (GAC) and will be used in place of reference assemblies. 

Therefore your assembly may not be correctly targeted for the framework you intend. [/home/travis/build/WeihanLi/MvcSimplePager/MvcSimplePager/MvcSimplePager.csproj]

• travis-ci build log
• appveyor build log

[dsplaisted]

@WeihanLi #335 covers building .NET Framework projects on non-Windows platforms.

If you don’t actually need the .NET Framework versions to be built when building on Linux, you could make the multi-targeting conditioned on what the current OS is. That’s what we do for the SDK tasks themselves: https://github.com/dotnet/sdk/blob/30baeae0a60f26214ffad743ddbbe4851375b4a2/src/Tasks/Microsoft.NET.Build.Tasks/Microsoft.NET.Build.Tasks.csproj#L7-L8

[dasMulli]

fyi I’ve summed up the current ways to build for net* on linux at https://stackoverflow.com/questions/44770702/build-nuget-package-on-linux-that-targets-net-framework/44773795#44773795