BindingContext not working if Content is in a separate class

[denmusic1992]

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Popup Ver. = 1.1.5.180

Hello! Let me explain the issue: I have a class called CommonPopupPage with empty content for using it anywhere and for not to copy/paste xaml code for init the page.

xaml looks like so:

<?xml version="1.0" encoding="utf-8" ?>
<pages:PopupPage xmlns="http://xamarin.com/schemas/2014/forms"
                 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                 xmlns:pages="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
                 xmlns:animations="clr-namespace:Rg.Plugins.Popup.Animations;assembly=Rg.Plugins.Popup"
                 x:Class="CommonClassesLibrary.CommonPopupPage"
                 CloseWhenBackgroundIsClicked="True">
    <pages:PopupPage.Animation>
        <animations:ScaleAnimation
            PositionIn="Center"
            PositionOut="Center"
            ScaleIn="1.2"
            ScaleOut="0.8"
            DurationIn="400"
            DurationOut="300"
            EasingIn="SinOut"
            EasingOut="SinIn"
            HasBackgroundAnimation="True"/>
    </pages:PopupPage.Animation>
    <Frame HorizontalOptions="Center"
           VerticalOptions="Center"
           CornerRadius="5"
           Margin="40"
           Padding="0">
        <StackLayout Orientation="Vertical" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" BackgroundColor="White">
            <AbsoluteLayout HorizontalOptions="Fill" VerticalOptions="Fill" BackgroundColor="Accent">
                <Label VerticalOptions="Fill" HorizontalOptions="Fill" HorizontalTextAlignment="Center" Margin="50, 0, 50, 0" 
                       VerticalTextAlignment="Center" x:Name="HeaderName" Style="{StaticResource LabelSmallWhite}" AbsoluteLayout.LayoutBounds="0.5, 0.5, 1, 1"
                       AbsoluteLayout.LayoutFlags="All" x:FieldModifier="public" />
                <Button VerticalOptions="Center" HorizontalOptions="Center" WidthRequest="25"
                        HeightRequest="25" Clicked="ButtonCloseClicked" Image="close_button_black.png" Style="{StaticResource ButtonStandardWhite}"
                        AbsoluteLayout.LayoutBounds="1, 0, 50, 50" AbsoluteLayout.LayoutFlags="PositionProportional" />
            </AbsoluteLayout>
            <ContentView x:Name="CommonContent" x:FieldModifier="public" VerticalOptions="Center" HorizontalOptions="Center" />
        </StackLayout>
    </Frame>
</pages:PopupPage>

So I use it for my ListViewPopupPage, that is a ContentView:

<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:controls="clr-namespace:Plugin.InputKit.Shared.Controls;assembly=Plugin.InputKit"
             x:Class="ISSO_I.PopupTypes.MultiselectListView">
    <ContentView.Content>
        <StackLayout>
            <ListView RowHeight="70" Margin="5" ItemsSource="{Binding Items}" CachingStrategy="RecycleElement">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <StackLayout Orientation="Horizontal">
                                <controls:CheckBox IsChecked="{Binding IsChecked}" LabelPosition="After" Margin="10"
                                                   Type="Material" Text="{Binding Body}" TextColor="Black" />
                            </StackLayout>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
            <BoxView Color="Accent" HeightRequest="1" />
            <controls:CheckBox IsChecked="{Binding Path=AllChecked}" LabelPosition="After" Margin="10" Type="Material"
                               Text="(Выбрать все)" TextColor="Black" />
            <Button Style="{StaticResource ButtonStandard}" Margin="10" Text="Применить" Clicked="ButtonConfirmClicked"/>
        </StackLayout>
    </ContentView.Content>
</ContentView>

For this class data binding not working at all. But if I change it's type to, e.g. ContentPage, data binding works! What's wrong with my approach? Is it a bug?

[rotorgames]

@denmusic1992 How do you apply BindingContext?

[denmusic1992]

@rotorgames Will post my code of model, viewmodel and view.

MultiselectListView.xaml.cs:

public partial class MultiselectListView
	{

		public MultiselectListViewModel Vm;

		public event EventHandler ApplyConstrs;

		/// <summary>
		/// Для заголовка окна
		/// </summary>
		public const string Header = "Выбранные номера конструкций";

		public MultiselectListView (ObservableCollection<MultiselectItem> items)
		{
			InitializeComponent();
			//MultiListView.ItemsSource = _vm.Items;
			Vm = new MultiselectListViewModel(items);
			BindingContext = Vm;
		}
		...
	}

model.cs:

public class MultiselectListViewModel : INotifyPropertyChanged
    {
		/// <summary>
		/// Номера конструкций
		/// </summary>
	    private ObservableCollection<MultiselectItem> _items;
	    public ObservableCollection<MultiselectItem> Items
	    {
		    get => _items;
		    set
		    {
			    if (_items == value) return;
			    _items = value;
				OnPropertyChanged(nameof(Items));
		    }
	    }

	    private bool _allChecked;
	    public bool AllChecked
	    {
		    get => _allChecked;
		    set
		    {
			    if (_allChecked == value) return;
			    _allChecked = value;
				OnPropertyChanged(nameof(AllChecked));
				// Меняем все галочки
			    foreach (var item in Items)
			    {
				    item.IsChecked = _allChecked;
			    }
		    }
	    }

	    public MultiselectListViewModel(ObservableCollection<MultiselectItem> items)
	    {
		    Items = items;
	    }

	    #region INotify Staff

	    public event PropertyChangedEventHandler PropertyChanged;

	    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
	    {
		    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
	    }

	    #endregion
	    
    }

and model.cs:

public class MultiselectItem : INotifyPropertyChanged
    {

	    /// <summary>
	    /// Признак выбранного элемента
	    /// </summary>
	    private bool _isChecked;

	    public bool IsChecked
	    {
		    get => _isChecked;
		    set
		    {
				if(_isChecked == value) return;
			    _isChecked = value;
				OnPropertyChanged(nameof(IsChecked));
		    }
	    }

	    /// <summary>
	    /// Текст элемента
	    /// </summary>
	    public string Body { get; set; }

	    public event PropertyChangedEventHandler PropertyChanged;

	    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
	    {
		    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
	    }
    }

[rotorgames]

@denmusic1992 I can't see anything wrong that can refer to this plugin. I think the problem in your code but if you still think that the problem is in the plugin, please, create a simple project where I can replicate this issue. Thanks.

[ybadragon]

I am also able to replicate this issue, I'm using Fody.PropertyChanged for the PropertyChanged code. I've tested the code in a normal view and it works, but in a PopupPage it doesn't work.

[denmusic1992]

Hi @rotorgames ! Sorry for a very late answer, just now I've had some free time to create sample code. Here is zip archive with it inside: ListTestApp.zip

[EmilAlipiev]

your problem is probably with contentview that you are bindingcontext on contentview. if you try to set bindincontext of popuppage, it should be working.

[rotorgames]

@denmusic1992 Did you solve this issue or still get?