NavigationService

NavigationService

public class NavigationService : INavigationService
{
    #region Fields

    private INavigation navigation => (Application.Current.MainPage as Main.Views.MainPage)?.Detail.Navigation;

    private readonly IDictionary<string, Type> pageLookup = new Dictionary<string, Type>();

    #endregion

    #region Interface implementation

    public void RegisterPage(string pageKey, Type pageType)
    {
        if (this.pageLookup.ContainsKey(pageKey))
        {
            throw new ArgumentException("That pagekey is already registered", pageKey);
        }

        this.pageLookup[pageKey] = pageType;
    }

    public void NavigateTo(string pageKey, bool animated = true)
    {
        var pageType = this.pageLookup[pageKey] as Type;

        var page = ServiceLocator.Current.GetInstance(pageType) as Page;

        NavigateTo(page, animated);
    }

    public void NavigateTo(string pageKey, bool animated = true, params (string propertyName, object param)[] args)
    {
        var pageType = this.pageLookup[pageKey] as Type;

        if (pageType == null)
        {
            throw new ArgumentNullException(nameof(pageType));
        }

        var parameters = new List<NamedParameter>();

        foreach (var item in args)
        {
            parameters.Add(new NamedParameter(item.propertyName, item.param));
        }

        var page = App.Instance.Container.Resolve(pageType, parameters) as Page;

        if(page == null)
        {
            throw new NullReferenceException("Page cannot be empty!");
        }

        NavigateTo(page, animated);
    }

    public void GoBack()
    {
        navigation.PopAsync(true).Start();
    }

    #endregion

    #region Methods

    private void NavigateTo(Page page, bool animated = true)
    {
        if (page == null)
        {
            throw new ArgumentNullException(nameof(page));
        }

        var last = navigation.NavigationStack.LastOrDefault();
        if (last == null || last.GetType() != page.GetType())
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                navigation.PushAsync(page, animated);
            });
        }
    }

    #endregion
}