MvvmCross 6.0: How to pass parameter to App on initialization?

Question

after the update to MvvmCross 6.1.2 my code is telling me that the App-class has to have a parameterless constructor. The problem is that until now I passed the filepath to the database to the App using it's constructor.

var dbPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "MyDatabase.db");
return new App(dbPath);

There should be a way to do this, yet I haven't found information on it for MvvmCross 6.0. Can anyone help me out here?

Answer 1

Way 1:

Instead of passing database path into App constructor, you can get this path into Core, using Mvx registration.

public interface IDBPathService
{
    string GetDBPath();
}


public class  DBPathService : IDBPathService
{

    public string GetDBPath()
    {
         return Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "MyDatabase.db");
    }
}

In App.cs class there would be Initailize method which should be registering this implementation using

CreatableTypes() 
    .EndingWith("Service")
    .AsInterfaces()
    .RegisterAsLazySingleton();

Now you can get path using

var dbpath = Mvx.Resolve<IDBPathService>().GetDBPath();

Way 2:

Another simpler way is taking static property into your App.cs class and assign path directly from Native projects like.

In App.cs class define a static property:

public static string DBPath;

In Platform specific projects assign path like:

App.DBPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "MyDatabase.db");