Can't pass bound view model as command parameter

<CollectionView.ItemTemplate>
                <DataTemplate x:DataType="data:PhotoItemViewModel">
                    <Border StrokeThickness="1"
                            Padding="0">
                        <VerticalStackLayout>
                            <Grid>
                                <Image
                                    Source="{Binding ThumbnailImageSource}"
                                    Aspect="AspectFill"
                                    HeightRequest="120"
                                    WidthRequest="120">
                                    <Image.Behaviors>
                                        <toolkit:TouchBehavior
                                            
                                            LongPressCommand="{Binding x:DataType=ContentPage, Source={x:Reference Page}, Path=BindingContext.LongPressCommand}"
                                            LongPressCommandParameter="{Binding .}"/>
                                    </Image.Behaviors>
                                </Image>
                                
                                <CheckBox
                                    IsChecked="{Binding IsSelected}"
                                    IsVisible="{Binding x:DataType=ContentPage,Source={x:Reference Page}, Path=BindingContext.IsSelectionMode}"
                                    VerticalOptions="Start"
                                    HorizontalOptions="End"
                                    Margin="5"
                                    BackgroundColor="White"
                                    Opacity="0.8"/>
                            </Grid>
                        </VerticalStackLayout>
                    </Border>
                </DataTemplate>
            </CollectionView.ItemTemplate>
        </CollectionView>

Here I'm using a collection view to display a list of images, with the support of long press gesture on each image, implemented using CommunityToolkit.Maui's TouchBehavior. And my view model's LongPressCommand command is initialized with this method:

  private void OnPhotoLongPressed(PhotoItemViewModel photo)
    {
        IsSelectionMode = true;
        // photo.IsSelected = true;
    }

Now the issue is the photo passed from the command is always null.

Turns out there're just couple of things to add in order to have my original code to work:

1. Add BindingContext assignment to the behavior;

2. Set x:DataType to the BindingContext;

3. Use x:Reference to refer to the parent Image control and set its BindingContext to the behavior.

Hope this could be added to the documentation as this is quite a common scenario.