how to share fonction beetwin Unity3D and visual studio (windows store; win10, xaml)

I develop tactile applications on UWP (universal windows application). The app is carried on touch walls of 3 m long.
I need to integrate a unity3D module. For this I export from the PC Windows Store format, windows 10, xaml. In this 3D project I add zones of click that I have to recover in visual studio. The click triggers the launch of a video. We need to retrieve the variable.
I don’t know if it’s possible.
I found this page Unity - Manual: AppCallbacks class reference

Am I right that you want to trigger a event from Unity in Visual Studio to show a specific video in Native C# and Xaml code?

I dont know how it works with diffrent projects but I solved it by using the same project.

I done something before by exporting the project in unity for Windows 10 and added new Pages direct in this Project. Now you can add some events and static variables in the Unity scripts and fire them with your buttons. In your MainPage.cs code you can access these events and also your static variables.

So you got your event and a specific string or integer or whatever to choose the right video.

Is this what you really wanted?