Question/Issue: SetCurrentState from code behind

[glenn2223]

Am I doing something wrong or is this an issue?

---

Context

Changing the state causes the application to crash.

I was expecting it to throw here StateContainer.SetCurrentState(TestStateContainer, newState); but it's not. The button event finishes and then the application crashes

OS: Windows 10
.NET Version: 7
Toolkit version: 3.0.0

Simple code reproduction

Page

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
             x:Class="MyTest.Pages.TestPage">

    <VerticalStackLayout Padding="15">
        <Button Text="ChangeState" Clicked="Button_Clicked" />

        <ScrollView x:Name="TestStateContainer">
            <toolkit:StateContainer.StateViews>
                <Label x:Name="FirstStateView"
                   toolkit:StateView.StateKey="FirstState"
                   Text="First State" />

                <Label x:Name="SecondStateView"
                   toolkit:StateView.StateKey="SecondState"
                   Text="Second State" />
            </toolkit:StateContainer.StateViews>

            <Label Text="Default State" />
        </ScrollView>
    </VerticalStackLayout>
</ContentPage>

Code behind

namespace MyTest.Pages;

using System.Linq;
using CommunityToolkit.Maui.Layouts;

public partial class TestPage : ContentPage
{
    readonly List<string> _arr = new() { "FirstState", "SecondState" };

    public TestPage()
    {
        InitializeComponent();
    }

    void Button_Clicked(object sender, EventArgs e)
        => ChangeState(
            _arr
                .Where(x => 
                    x != StateContainer.GetCurrentState(TestStateContainer)
                )
                .ElementAt(0)
        );

    // IRL: I call this from several places, which is why it's a method
    void ChangeState(string newState)
    {
        // Me debugging stuff
        var z = StateContainer.GetStateViews(TestStateContainer);
        var y = StateContainer.GetCurrentState(TestStateContainer);


        // Actual thing
        StateContainer.SetCurrentState(TestStateContainer, newState);
        // More things IRL


        // More debugging
        var x = StateContainer.GetCurrentState(TestStateContainer);
        var w = StateView.GetStateKey(FirstStateView);
    }
}

Note: Sorry if it's obvious. I'm new(ish) to MAUI, XAML and the toolkit 😉

[nicjay]

Try changing your StateContainer element to a layout element like VerticalStackLayout. You can still wrap a ScrollView around it.

<ScrollView>
  <VerticalStackLayout x:Name="TestStateContainer">
    <toolkit:StateContainer.StateViews>
      ...

[glenn2223]

That's sorted it. THANK YOU!!

P.s, sorry for the delay - away from my PC

[CliffAgius]

Closed as answered