Problem

<?xml version="1.0" encoding="UTF-8" ?>
<ContentView
    x:Class="App1.AllReviews"
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:customcontrol="clr-namespace:App1">
    <ContentView.Content>
        <AbsoluteLayout>
            <Frame
                Margin="0"
                AbsoluteLayout.LayoutBounds="0, 0, 1, 1"
                AbsoluteLayout.LayoutFlags="All"
                BackgroundColor="White"/>
            <StackLayout>
                <ImageButton Source="close_iconn" HorizontalOptions="Start" BackgroundColor="Transparent" Margin="5, 5, 0, 0" Clicked="onCloseReviews"/>

                <CollectionView

                    ItemsSource="{Binding AllReview}">
                    <CollectionView.ItemTemplate>
                        <DataTemplate>
                            <StackLayout Margin="0,10,0,30">
                                <StackLayout HorizontalOptions="StartAndExpand" Orientation="Horizontal">
                                    <Image
                                        Margin="25,0,0,0"
                                        HorizontalOptions="Start"
                                        Source="face" />
                                    <StackLayout Orientation="Vertical">
                                        <Label Text="{Binding nickName}" TextColor="#616161" />
                                        <StackLayout Orientation="Horizontal" VerticalOptions="Center" HeightRequest="15">
                                            <customcontrol:RattingBar
                                                EmptyStarImage="emptystar"
                                                FillStarImage="fillstar"
                                                HorizontalOptions="Start"
                                                ImageHeight="15"
                                                ImageWidth="15"
                                                SelectedStarValue="4" />
                                            <Label Text="{Binding raiting}" TextColor="#616161" />
                                        </StackLayout>
                                    </StackLayout>
                                </StackLayout>
                                <CarouselView
                                    HeightRequest="120"
                                    ItemsSource="{Binding photos}"
                                    PeekAreaInsets="80">
                                    <CarouselView.GestureRecognizers>
                                        <TapGestureRecognizer NumberOfTapsRequired="1" />
                                    </CarouselView.GestureRecognizers>
                                    <CarouselView.ItemTemplate>
                                        <DataTemplate>
                                            <StackLayout>
                                                <Frame
                                                    Margin="0"
                                                    Padding="0"
                                                    BorderColor="DarkGray"
                                                    CornerRadius="0"
                                                    HasShadow="True"
                                                    HeightRequest="120"
                                                    WidthRequest="190">
                                                    <StackLayout>

                                                        <Image
                                                            Aspect="AspectFill"
                                                            HeightRequest="120"
                                                            Source="{Binding .}"
                                                            WidthRequest="190" />

                                                    </StackLayout>
                                                </Frame>
                                                <VisualStateManager.VisualStateGroups>
                                                    <VisualStateGroup x:Name="CommonStates">
                                                        <VisualState x:Name="CurrentItem">
                                                            <VisualState.Setters>
                                                                <Setter Property="Scale" Value="1" />
                                                            </VisualState.Setters>
                                                        </VisualState>
                                                        <VisualState x:Name="PreviousItem">
                                                            <VisualState.Setters>
                                                                <Setter Property="Opacity" Value="0.5" />
                                                            </VisualState.Setters>
                                                        </VisualState>
                                                        <VisualState x:Name="NextItem">
                                                            <VisualState.Setters>
                                                                <Setter Property="Opacity" Value="0.5" />
                                                            </VisualState.Setters>
                                                        </VisualState>
                                                        <VisualState x:Name="DefaultItem">
                                                            <VisualState.Setters>
                                                                <Setter Property="Opacity" Value="0.25" />
                                                            </VisualState.Setters>
                                                        </VisualState>
                                                    </VisualStateGroup>
                                                </VisualStateManager.VisualStateGroups>
                                            </StackLayout>
                                        </DataTemplate>
                                    </CarouselView.ItemTemplate>
                                </CarouselView>

                                <Frame
                                    Margin="25,0,25,0"
                                    BackgroundColor="#EBEBEB"
                                    CornerRadius="20"
                                    HorizontalOptions="FillAndExpand">
                                    <Label
                                        MinimumHeightRequest="55"
                                        Text="{Binding review}"
                                        TextColor="#616161" />
                                </Frame>
                            </StackLayout>
                        </DataTemplate>
                    </CollectionView.ItemTemplate>
                </CollectionView>
            </StackLayout>
        </AbsoluteLayout>
    </ContentView.Content>
</ContentView>