I am programmatically initializing the choice of an merchandise in a CollectionView earlier than rendering it. On iOS, the UI exhibits nothing chosen when the CollectionView is first rendered although I bind SelectedItem to the property that’s programmatically initialized to level to one of many CollectionView objects. After I click on on an merchandise, the choice of objects works as anticipated. This all works as I count on on Android.
Right here is my easy ViewModel for reproducing this challenge:
namespace CollectionViewRepro
{
public partial class CollectionViewData : ObservableObject
{
public Checklist<string> CollectionViewElements { get; non-public set; }
[ObservableProperty]
non-public string chosen;
public CollectionViewData()
{
CollectionViewElements = new()
{
" 1 ",
" 2 ",
" 3 "
};
Chosen = CollectionViewElements[1];
}
}
}
Right here is the XAML:
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:collectionviewrepro="clr-namespace:CollectionViewRepro"
x:DataType="collectionviewrepro:CollectionViewData"
x:Class="CollectionViewRepro.MainPage">
<VerticalStackLayout
Margin="10,30,10,0"
HorizontalOptions="Middle">
<Label Textual content="Pattern Label - Centered" HorizontalTextAlignment="Middle"/>
<CollectionView ItemsSource="{Binding CollectionViewElements}" HorizontalOptions="Middle" SelectionMode="Single"
SelectedItem="{Binding Chosen}" HeightRequest="20">
<CollectionView.ItemsLayout>
<LinearItemsLayout Orientation="Horizontal"/>
</CollectionView.ItemsLayout>
</CollectionView>
<HorizontalStackLayout Margin="0,20,0,0">
<Label Textual content="That is the chosen merchandise: "/>
<Label Textual content="{Binding Chosen}"/>
</HorizontalStackLayout>
</VerticalStackLayout>
</ContentPage>
Right here is the code-behind:
public partial class MainPage : ContentPage
{
non-public CollectionViewData vm { get; set; }
public MainPage()
{
vm = new CollectionViewData();
InitializeComponent();
BindingContext = vm;
}
}
Here’s what the preliminary rendering seems to be like on an Android emulator:
On an iPhone emulator:
Notice that the textual content beneath the CollectionView within the iOS picture verifies that the Chosen property does level to “2” when the web page is rendered, however the 2 within the CollectionView is not highlighted. If I click on on any of the objects, it’s then highlighted and “That is the chosen merchandise:” exhibits the right merchandise. So, I do know the Chosen property is being outlined correctly and the TwoWay Binding of the CollectionView SelectedItem is working correctly.
This positively looks like a bug to me, nevertheless, I would love to listen to completely different views or prompt workarounds. I’ve thought of giving Syncfusion’s ListView a go.
Please forgive this very temporary rant… I am getting fairly pissed off and discouraged by the continual stream of bugs and inconsistencies throughout Android and iOS which have delayed my releases by many weeks.
