Adding Windows.winmd to a UWP project cause conflict

Question

I am trying to create a UWP project With VS 2017 and MVVMLight tageting Windows 10 version 1803 to 1809. It is a WPF application.

After some days of work, my solution compile and execute correctly and my main view display correctly. Now, I need to add support for a StorageDevice and VS suggest to add a reference to Windows.winmd. Now, StorageDevice is recognized but this add conflicts message and build errors.

The conflicts are all with Windows.Foundation.UniversalApiContract v7.0.0.0 for different classes including

I have many years of experience in desktop apps, but I admit I am a rookie in UWP. I try to grasp the concept, but in my point of view, it changes year after year and I don't understand the interrelation between all the components and the concept of winmd. So, I am lost and don't see any solution path or similar problem solution with google.

To reproduce the problem :

1. Create a MVVMLight universal windows application from Visual Studio 2017.
2. Add the following at the end of the constructor of the App class in app.xaml.cs. It will look like this :

public App()
{
   InitializeComponent();
   Suspending += OnSuspending;

   StorageFolder x = StorageDevice.FromId("");
}

3. Add usings for the following namespaces :

   • using Windows.Devices.Portable;
   • using Windows.Storage;

4. Compile. It will show an error for the line added in point 2 and suggest to add a reference to Windows.winmd. StorageDevice is defined in the Windows.Devices.Portable namespace.

5. Accept the suggestion to add a reference to Windows.winmd. The previous error disappear, but many conflicts (error CS0433) will appear, for example :

Erreur  CS0433  Le type 'ApplicationExecutionState' existe dans 'Windows.Foundation.UniversalApiContract, Version=3.0.0.0, Culture=neutral, PublicKeyToken=null, ContentType=WindowsRuntime' et 'Windows, Version=255.255.255.255, Culture=neutral, PublicKeyToken=null, ContentType=WindowsRuntime'    MvvmLight2  D:\Code\App.xaml.cs 41  Actif

Translated to english :

Error   CS0433  The type 'ApplicationExecutionState' exist in 'Windows.Foundation.UniversalApiContract, Version=3.0.0.0, Culture=neutral, PublicKeyToken=null, ContentType=WindowsRuntime' and 'Windows, Version=255.255.255.255, Culture=neutral, PublicKeyToken=null, ContentType=WindowsRuntime' MvvmLight2  D:\Code\App.xaml.cs 41  Actif

Answer 1

StorageDevice is included in Windows Desktop Extension SDK, you do not need to add reference to Windows.winmd.

Follow the steps to add reference to 'Windows Desktop Extension':

Right click the 'Reference' of your project -> Add Reference -> Universal Windows -> Extensions -> Windows Desktop Extensions for the UWP .