How does one create a directory with a PCL
.net, c#, mono, portable-class-library
Solution
There is no built-in file and directory I/O support in PCL, since this functionality differs from platform to platform. However, to circumvent this issue you could reference PCLStorage in your portable class library project.
PCLStorage provides a portable abstraction layer library for file and directory I/O that you would reference in your portable class library. In your platform-specific application implementation, you would incorporate the corresponding implementation library of this abstraction layer.
PCLStorage is applicable to .NET Framework 4 and higher, Silverlight 4 and higher, Windows Phone 7.5 and higher, and Windows Store apps. It relies on `async` and `await`, which means that it is dependent on the BCL Async package when used e.g. with .NET 4, Silverlight and Windows Phone 7.5.
You might also want to have a look at the MvvmCross File plug-in. MvvmCross is portable "by nature" and the File plug-in provides relevant file and directory I/O functionality as synchronous methods. MvvmCross portable libraries are currently applicable to .NET Framework 4.5, Silverlight 4 and higher, Windows Phone 7.5 and higher, Windows Store apps, Xamarin.iOS and Xamarin.Android.
Problem
While dealing with creating a Portable Class Library out of current code for a project, some workarounds are fairly obvious and some are problematic. `System.IO.Directory` is non-PCL and I still need to be able to create a directory before creating files inside them. How do you create a folder in C# without being able to call `Directory.CreateDirectory(..)`?