CommunityToolkit.Maui.Core.Views.MauiPopup throws System.ObjectDisposedException on Close() - maui

Question

The following code results in a System.ObjectDisposedException on the line Close(result); in BarcodeScannerPopup.xaml.cs when a barcode is detected by the CameraBarcodeReaderView.
The detected barcode is correctly displayed in the label in BarcodePage.
Any idea why this exception is thrown?
BarcodePage.xaml
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage
x:Class="MyApp.BarcodePage"
x:DataType="vm:BarcodeViewModel"
xmlns:vm="clr-namespace:MyApp.ViewModels"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns="http://schemas.microsoft.com/dotnet/2021/maui">
<VerticalStackLayout
Margin="20">
<Label
Text="{Binding Barcode}"/>
<Button
Command="{Binding ScanBarcodeClickCommand}"
Text="Scan barcode"/>
</VerticalStackLayout>
</ContentPage>
BarcodePage.xaml.cs
using MyApp.ViewModels;
namespace MyApp.Views;
public partial class BarcodePage : ContentPage
{
public BarcodePage(BarcodeViewModel viewModel)
{
InitializeComponent();
BindingContext = viewModel;
}
}
BarcodeScannerPopup.xaml
<?xml version="1.0" encoding="utf-8" ?>
<toolkit:Popup
x:Class="MyApp.BarcodeScannerPopup"
xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:zxing="clr-namespace:ZXing.Net.Maui.Controls;assembly=ZXing.Net.MAUI"
xmlns="http://schemas.microsoft.com/dotnet/2021/maui">
<VerticalStackLayout
Margin="20">
<Label
Text="Add a barcode by scanning it."
VerticalOptions="Center"
HorizontalOptions="Center"/>
<zxing:CameraBarcodeReaderView
x:Name="barcodeReader"
BarcodesDetected="BarcodesDetected"
HeightRequest="300"
IsDetecting="True"
Margin="5"
WidthRequest="300"/>
</VerticalStackLayout>
</toolkit:Popup>
BarcodeScannerPopup.xaml.cs
using CommunityToolkit.Maui.Views;
using ZXing.Net.Maui;
namespace MyApp.Views;
public partial class BarcodeScannerPopup : Popup
{
public BarcodeScannerPopup()
{
InitializeComponent();
barcodeReader.Options = new BarcodeReaderOptions
{
AutoRotate = true,
Multiple = false
};
}
private void BarcodesDetected(object sender, BarcodeDetectionEventArgs e)
{
var result = e.Results[0].Value;
Close(result);
}
}
BarcodeViewModel.cs
using CommunityToolkit.Maui.Views;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using MyApp.Views;
namespace MyApp.ViewModels;
public partial class BarcodeViewModel : ObservableObject
{
[ObservableProperty]
private string _barcode;
private BarcodeScannerPopup _popup = new BarcodeScannerPopup();
[RelayCommand]
public async Task ScanBarcodeClick()
{
Barcode = (string)await Application.Current.MainPage.ShowPopupAsync(_popup);
}
}

Answer 1

#ToolmakerSteve was right. The CameraBarcodeReaderView continues sending data which results in the System.ObjectDisposedException. setting the IsDetecting property to false prevents this. As this was a PoC I didn't add a proper null check on e, so I've added as a good coding practise in this example.
BarcodeScannerPopup.xaml.cs
using CommunityToolkit.Maui.Views;
using ZXing.Net.Maui;
namespace MyApp.Views;
public partial class BarcodeScannerPopup : Popup
{
public BarcodeScannerPopup()
{
InitializeComponent();
barcodeReader.Options = new BarcodeReaderOptions
{
AutoRotate = true,
Multiple = false
};
}
private void BarcodesDetected(object sender, BarcodeDetectionEventArgs e)
{
var result = e?.Results?.Any() == true
? e.Results[0].Value
: string.Empty;
IsDetecting = false;
Close(result);
}
}