I have three classes involved in my problem. PopupView, CardView, and TestPopup. PopupView represents a base class for popups, and uses CardView, to display 3 ContentView linerally with header body and footer. TestPopup inherits PopupView which itself exposes a Body property that sets the CardView Body property with the latter.

Please note that PopupView and CardView are in a sepparate class library, it seems to matter because if I define TestPopup in the class library everything works fine. So at this point I think either I am doing something horribly wrong or there is a bug maybe someone is aware of in MAUI.

Here is the code:

   <tt:PopupView 
        xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
        xmlns:mct="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
        xmlns:tt="http://barambibol.io/dotnet/maui/timertoolkit"
        x:Class="TestApp.PopupTest"
        >
        <tt:PopupView.Body>
            <Label Text="AAA"/>
        </tt:PopupView.Body>
    </tt:PopupView>
    
public partial class PopupTest : PopupView
{
    public PopupTest()
    {
    

InitializeComponent();
        }
    }

public partial class PopupView : PopupBase
{
    public PopupView()
    {
        InitializeComponent();
    }

    protected override void OnSizeAllocated(double width, double height)
    {
        base.OnSizeAllocated(width, height);

        if (width != -1 && height != -1)
        {
            // Here cardView is null. bodyContentView however is not null.
            cardView.WidthRequest = width * TimerToolkitConfig.PopupPageWidthRatio;
            cardView.MinimumHeightRequest = TimerToolkitConfig.ConfirmationPopupContentHeight;
            cardView.MaximumHeightRequest = height * TimerToolkitConfig.PopupPageHeightRatioMax;

            bodyContentView.Content = Body;
        }
    }
}

Here when I try to access an element from the view in code-behind, one of them is null. It is “cardView”. “bodyContentView”, which is a child of “cardView”, is not null. How is that even possible ? Any light on this would be greatly appreciated I honestyl have absolutely no clue how this can happen