I have a portable class library project that targets .NET 4.6 and Universal Windows Platform. This class library contains just one class with the following line of code in its constructor:
Directory.CreateDirectory(Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString()));
Now I create a new .NET 4.6 console application project in the same solution and add a project reference to the portable class library. Calling the method that houses the above line of code results in the following exception at runtime:
Could not load file or assembly 'System.IO.FileSystem, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
What am I doing wrong here? There are no compile-time errors or warnings.
It seems that System.IO.FileSystem is a library delivered via NuGet, as part of the Microsoft.NETCore mega-package. Okay, perhaps I need to explicitly add this package to any project that uses my portable class library. I attempt to do so.
Could not install package 'Microsoft.NETCore.Platforms 1.0.0'. You are trying to install this package into a project that targets '.NETFramework,Version=v4.6', but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.
No luck with this approach.
While there is no clear info on the web, I read a few tidbits about a new project.json based NuGet harness or build system. Just to experiment, I created the following project.json file in my console application project:
{
"dependencies": {
},
"frameworks": {
"net46": { }
},
"runtimes": {
"win-anycpu": { }
}
}
It works! The runtime error goes away! However, I soon found that this was either not the right solution or not a complete solution. I started writing some code to read configuration section values, which involved making use of the IConfigurationSectionHandler
interface, and got the following compile-time error:
error CS0246: The type or namespace name 'IConfigurationSectionHandler' could not be found (are you missing a using directive or an assembly reference?)
This interface is part of the System assembly. I see a reference to this assembly, but it has a yellow exclamation mark icon, and a warning appears in the warnings window:
The referenced component 'System' could not be found.
This is where I ran out of ideas. Am I missing something totally obvious?
I have found the solution. My initial attempt was to install the Microsoft.NETCore package into the console application, resulting in the error shown in my original post.
However, if I install only the narrowly-scoped packages, e.g. System.IO.FileSystem, then I achieve success and the application works correctly. Apparently there is something special about the Microsoft.NETCore "master package" that prevents it from correctly installing into dependent projects.
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