ImageBox

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace NewsFeed.Controls
{
    public class ImageBox : ContentView
    {
        private Image imageElement;
        private Label labelElement;
        private BoxView boxViewElement;

        public static readonly BindableProperty BoxBackgroundColorProperty =
            BindableProperty.Create("BoxBackgroundColor", typeof(Color), typeof(ImageBox), Color.Default);
        public static readonly BindableProperty ImageSourceProperty =
            BindableProperty.Create("ImageSource", typeof(string), typeof(ImageBox), string.Empty);
        public static readonly BindableProperty ContentTextProperty =
            BindableProperty.Create("ContentText", typeof(string), typeof(ImageBox), string.Empty);

        public Color BoxBackgroundColor
        {
            get { return (Color)GetValue(BoxBackgroundColorProperty); }
            set { SetValue(BoxBackgroundColorProperty, value); }
        }

        public string ImageSource
        {
            get { return (string)GetValue(ImageSourceProperty); }
            set { SetValue(ImageSourceProperty, value); }
        }
        public string ContentText
        {
            get { return (string)GetValue(ContentTextProperty); }
            set { SetValue(ContentTextProperty, value); }
        }

        public ImageBox()
        {
            var mainLayout = new RelativeLayout();

            boxViewElement = new BoxView();
            {
                BackgroundColor = BoxBackgroundColor
            };
            mainLayout.Children.Add(boxViewElement,
                Constraint.Constant(0),
                Constraint.Constant(0),
                Constraint.RelativeToParent((p) => p.Width),
                Constraint.RelativeToParent((p) => p.Height));

            imageElement = new Image()
            {
                Aspect = Aspect.AspectFit
            };
            imageElement.Source = ImageSource;
            mainLayout.Children.Add(imageElement,
                Constraint.RelativeToView(boxViewElement, (p, v) => v.Width * 0.2),
                Constraint.RelativeToView(boxViewElement, (p, v) => (v.Height * 0.6) / 2 - v.Width * 0.25),
                Constraint.RelativeToView(boxViewElement, (p, v) => v.Width * 0.6),
                Constraint.RelativeToView(boxViewElement, (p, v) => v.Width * 0.6));

            labelElement = new Label();
            labelElement.FontSize = Device.GetNamedSize(NamedSize.Small, typeof(Label));
            labelElement.Text = ContentText;
            labelElement.TextColor = Color.White;
            labelElement.HorizontalTextAlignment = TextAlignment.Center;
            labelElement.VerticalTextAlignment = TextAlignment.Center;

            mainLayout.Children.Add(labelElement,
                Constraint.RelativeToParent((p) => p.Width * 0.025),
                Constraint.RelativeToParent((p) => p.Height * 0.625),
                Constraint.RelativeToParent((p) => p.Width * 0.95),
                Constraint.RelativeToParent((p) => p.Height * 0.325));

            Content = mainLayout;
        }

        protected override void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            base.OnPropertyChanged(propertyName);
            if (propertyName.Equals(BoxBackgroundColorProperty.PropertyName))
            {
                boxViewElement.BackgroundColor = BoxBackgroundColor;
            }
            else if (propertyName.Equals(ImageSourceProperty.PropertyName))
            {
                imageElement.Source = ImageSource;
            }
            else if (propertyName.Equals(ContentTextProperty.PropertyName))
            {
                labelElement.Text = ContentText;
            }
        }

    }
}