I'm trying to get a Xamarin Forms solution to build from the command line as part of a build script using the command dotnet build <solution.sln>. Most of the projects in the solution build; however, two projects fail with this error message: error MSB6006: "csc.exe" exited with code 1.(on Ubuntu) and error MSB6006: "csc.exe" exited with code 8. (on Mac).

I have running Ubuntu 18.04 (using Windows subsystem for Linux) and MacOS 10.13.6 on separate machines.

I have also tried to run dotnet build <solution.sln> from the windows command line which prints out this error message instead:

error MSB4062: The "XamarinLive.Build.XamarinLiveTask" task could not be loaded from the assembly C:\Users\Jason.nuget\packages\livexaml\2.1.22\build\XamarinLive.Build.dll. Could not load file or assembly 'Microsoft.Build.Utilities.v4.0, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask.

However, the solution works and builds fine from within VS2017 (Version 15.9.7). I've tried scouring the binary log that is generated but I can't make much sense of it and there doesn't seem to be any obvious errors (on Ubuntu & Mac). Could the windows error message be related in some way?

The projects that are failing target netstandard 2.0 (The same as the projects that do build). The version returned by dotnet --version on all 3 environments is 2.1.504.

Any help would be greatly appreciated.

1 Answers

Lance Li-MSFT On Best Solutions

You need to use msbuild.exe instead of dotnet build for this situation.

msbuild.exe runs on full framework while dotnet buildruns on .NET Core, and most of the build tasks don't support that.

When you build them in VS,it actually calls the msbuild.exe to build the solution.So you can build it well by developer command prompt since it also calls the msbuild.exe.

For vs2017, you can find it in C:\Program Files (x86)\Microsoft Visual Studio\2017\Edition\MSBuild\15.0\Bin.

More details see Martin's answer from this similar issue. Thanks to his detailed description!