Don't work with Unity - NullReferenceException

[Neogeekmo]

I need to retrieve the path to my phone from the computer to copy/paste backup files to it.
After adding the nuget package to unity, it can't find my devices.
So I have this error:

NullReferenceException: Object reference not set to an instance of an object
MediaDevices.MediaDevice.GetDevices () (at <016781043aa441d5b0169b9d5116ee77>:0)
ManageSaves.CopySaveFromDevice () (at Assets/Scripts/ManageSaves.cs:65)
ManageSaves.Testing () (at Assets/Scripts/ManageSaves.cs:57)
MainMenu.Testing () (at Assets/Scripts/MainMenu.cs:69)
UnityEngine.Events.InvokableCall.Invoke () (at <23a7799da2e941b88c6db790c607d655>:0)
UnityEngine.Events.UnityEvent.Invoke () (at <23a7799da2e941b88c6db790c607d655>:0)
UnityEngine.UI.Button.Press () (at C:/Program Files/Unity/Hub/Editor/2019.3.14f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/UI/Core/Button.cs:68)
UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at C:/Program Files/Unity/Hub/Editor/2019.3.14f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/UI/Core/Button.cs:110)
UnityEngine.EventSystems.ExecuteEvents.Execute (UnityEngine.EventSystems.IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at C:/Program Files/Unity/Hub/Editor/2019.3.14f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/ExecuteEvents.cs:50)
UnityEngine.EventSystems.ExecuteEvents.Execute[T] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.ExecuteEvents+EventFunction`1[T1] functor) (at C:/Program Files/Unity/Hub/Editor/2019.3.14f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/ExecuteEvents.cs:261)
UnityEngine.EventSystems.EventSystem:Update() (at C:/Program Files/Unity/Hub/Editor/2019.3.14f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/EventSystem.cs:377)

A possible solution... that you know ?

[Bassman2]

According to the information in Wikipedia, Unity uses the Mono framework for scripting. MediaDevices does not support Mono because Mono has no COM support and MediaDevices is a wrapper for the Windows MTP COM interface.

[Neogeekmo]

All right, thanks for your answer. I'll try to find another way.

[Bassman2]

According to my information, Mono can call methods in DLLs. I.e. if you pack the COM access into your own DLL and then call it from Unity, it should work.

[Neogeekmo]

That's what I wanted to try to do but I'm still looking for another way to implement it directly in a unity script without having to code my dll .