Build errors when multi-targeting in csproj file

.net .net-core visual-studio-2017 csproj
Nate Barbettini picture Nate Barbettini · Mar 28, 2017 · Viewed 8.3k times · Source

I'm trying to build a class library that multi-targets both .NET 4.5.1 and .NET Standard 1.3. According to the documentation, I should be able to do this:

<PropertyGroup>
  <TargetFrameworks>net451;netstandard1.3</TargetFrameworks>
</PropertyGroup>

However, when I try to build, I get these odd errors:

Cannot infer TargetFrameworkIdentifier and/or TargetFrameworkVersion from TargetFramework='net451'. They must be specified explicitly.

MSB3645 .NET Framework v3.5 Service Pack 1 was not found. In order to target ".NETFramework,Version=v1.3", .NET Framework v3.5 Service Pack 1 or later must be installed.

MSB3644 The reference assemblies for framework ".NETFramework,Version=v1.3" 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.

If I specify the target framework identifiers manually, it builds fine:

<PropertyGroup>
  <TargetFrameworks>net451;netstandard1.3</TargetFrameworks>
</PropertyGroup>
<PropertyGroup Condition="'$(TargetFramework)' == 'net451'">
  <TargetFrameworkIdentifier>.NETFramework</TargetFrameworkIdentifier>
</PropertyGroup>
<PropertyGroup Condition="'$(TargetFramework)' == 'netstandard1.3'">
  <TargetFrameworkIdentifier>.NETStandard</TargetFrameworkIdentifier>
</PropertyGroup>

I'm using Visual Studio 2017 Community. Am I doing something wrong here?

Answer

mcintyre321 picture mcintyre321 · Mar 29, 2017

Have you definitely written

<TargetFrameworks>net451;netstandard1.3</TargetFrameworks>

and not

<TargetFramework>net451;netstandard1.3</TargetFramework>

?

I was getting the same error until I added the missing s

Related questions

Detected package downgrade warning (dotnet core, vs 2017)

I have just updated all my nuget packages for my solution (dotnet core 1.1 project). I am now getting the following warnings and I don't really know what they mean. Update: I am still getting warnings mentioned above. My web projects …

Read More
Error NU1605 Detected package downgrade

I am experiencing the following NU1605 dependency errors in my netcoreapp2.0 console application: NU1605 Detected package downgrade: System.Diagnostics.Debug from 4.3.0 to 4.0.11. Reference the package directly from the project to select a different version. MyProject -> Colorful.Console 1.2.6 -&…

Read More
How do I exclude files/folders from a .NET Core/Standard project?

In .NET Core and .NET Standard projects, if you put files and folders within the project directory, they are automatically picked up by Visual Studio; essentially they are part of the project. What if I have files/folders in there …

Read More