How to access existing item inside TabViewItem

Question

Why is it my reference to an existing map control isn't working?

1. My main page loads another page inside the main page Grid
2. The loaded page is a TabView containing a few TabViewItems
3. In 1 of the TabViewItems there is a MapControl
4. I want to access the MapControl dynamically to add markers to it

I tried using MapControl mapControl = pageMap.MyMapControl; but it's not working. Why?

MainPage.xaml

<Grid x:Name="MainGrid">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <StackPanel Grid.Row="0">
        <TextBlock Text="Hello World" />
    </StackPanel>
    <controls:TabView
        x:FieldModifier="public"
        Grid.Row="1"
        x:Name="MainTabs"
        TabWidthBehavior="Actual"
        CanCloseTabs="False"
        IsCloseButtonOverlay="False"
        CanDragItems="False"
        CanReorderItems="False"
        AllowDrop="False">
    </controls:TabView>
</Grid>

MainPage.xaml.cs

    public sealed partial class MainPage: Page
    {
        public MainPage()
        {
            this.InitializeComponent();

            var mapPage= new MapPage();

            TabView tabView = mainPage.MainTabs;

            var tab1 = new TabViewItem { Header = "Map" };
            tabView.Items.Add(tab1);

            var tab2 = new TabViewItem { Header = "Tab 2" };
            tabView.Items.Add(tab2);

            var tab3 = new TabViewItem { Header = "Tab 3" };
            tabView.Items.Add(tab3);

            tabView.SelectedItem = tab1;

            // 1st tab contents
            var mapPage = new MapPage();
            MapControl mapControl = pageMap.MyMapControl; ??

            tab1.Content = mapPage;

            MainGrid.Children.Add(pageTabs);
        }
    }

Map page

    <Grid x:Name="MapGrid">
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>

        <Maps:MapControl
            Grid.Row="0"
            x:Name="MyMapControl"  
            MapServiceToken="[token]"
            ZoomLevel="8"/>
    </Grid>

Answer 1

Hello,

Welcome to Microsoft Q&A!

May I know what is the pageMap control? I can't find an element called pageMap. And what is the pageTabs control?
Another thing is that we call object.property to get the property we need. Is MyMapControl a property of pageMap?

A simple solution for this is that you could create a public MapControl property in the pageMap, so that you could get it when you could get the pageMap property.

Like this:

public MapControl theMapControl { get; set; }  

public MapPage()
{
    this.InitializeComponent();
     theMapControl = MyMapControl;
}

If you have other questions, please let me know.
Thank you.