Xamarin Forms Label control with rounded rects. Invisible for configurable value.

RoundRectLabel.cs

// RoundRectLabel.cs

using System;
using Xamarin.Forms;

namespace App
{
	public class RoundRectLabel : Label
	{
		public static readonly BindableProperty BorderColorProperty = 
			BindableProperty.Create<RoundRectLabel, Color> (p => p.BorderColor, Color.Transparent);

		public static readonly BindableProperty BorderWidthProperty = 
			BindableProperty.Create<RoundRectLabel, float> (p => p.BorderWidth, 0);

		public static readonly BindableProperty CornerRadiusProperty = 
			BindableProperty.Create<RoundRectLabel, float> (p => p.CornerRadius, 0);

		public static readonly BindableProperty HiddenValueProperty = 
			BindableProperty.Create<RoundRectLabel, string> (p => p.HiddenValue, null);

		protected override void OnBindingContextChanged ()
		{
			base.OnBindingContextChanged ();
			UpdateVisible ();
		}

		public Color BorderColor 
		{
			get
			{
				return (Color)GetValue (BorderColorProperty);
			}
			set
			{
				SetValue (BorderColorProperty, value);
			}
		}

		public float BorderWidth 
		{
			get
			{
				return (float)GetValue (BorderWidthProperty);
			}
			set
			{
				SetValue (BorderWidthProperty, value);
			}
		}

		public float CornerRadius 
		{
			get
			{
				return (float)GetValue (CornerRadiusProperty);
			}
			set
			{
				SetValue (CornerRadiusProperty, value);
			}
		}

		public string HiddenValue
		{
			get
			{
				return (string)GetValue(HiddenValueProperty);
			}
			set
			{
				SetValue (HiddenValueProperty, value);
				UpdateVisible ();
			}
		}

		private void UpdateVisible ()
		{
			if (String.IsNullOrEmpty (Text) || Text != HiddenValue)
			{
				IsVisible = true;
				return;
			}

			IsVisible = false;
		}

		public RoundRectLabel ()
		{
		}
	}
}

// RoundRectLabelRenderer.cs

using System;
using Xamarin.Forms;
using App;
using App.iOS;
using Xamarin.Forms.Platform.iOS;
using UIKit;

[assembly: ExportRenderer(typeof(RoundRectLabel), typeof(RoundRectLabelRenderer))]

namespace App.iOS
{
	public class RoundRectLabelRenderer : LabelRenderer
	{
		public RoundRectLabelRenderer ()
		{
		}

		protected override void OnElementPropertyChanged (object sender, System.ComponentModel.PropertyChangedEventArgs e)
		{
			base.OnElementPropertyChanged (sender, e);

//			var label = Element as RoundRectLabel;

			if (e.PropertyName == RoundRectLabel.BackgroundColorProperty.PropertyName)
			{
				SetNeedsLayout ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.BorderColorProperty.PropertyName)
			{
				SetNeedsLayout ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.BorderWidthProperty.PropertyName)
			{
				SetNeedsLayout ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.CornerRadiusProperty.PropertyName)
			{
				SetNeedsLayout ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.HiddenValueProperty.PropertyName)
			{
				SetNeedsLayout ();
				return;
			}
		}

		public override void LayoutSubviews ()
		{
			base.LayoutSubviews ();
		
			var label = Element as RoundRectLabel;

			Layer.BorderWidth = label.BorderWidth;
			Layer.CornerRadius = label.CornerRadius;
			Layer.BackgroundColor = label.BackgroundColor.ToCGColor ();
			Layer.BorderColor = label.BorderColor.ToCGColor ();
		}
	}
}

// RoundRectLabelRenderer.cs

using System;
using Xamarin.Forms.Platform.Android;
using Android.Graphics.Drawables;
using Android.Views;
using Xamarin.Forms;
using App;
using App.Droid;

[assembly: ExportRenderer(typeof(RoundRectLabel), typeof(RoundRectLabelRenderer))]

namespace App.Droid
{
	public class RoundRectLabelRenderer : LabelRenderer
	{
		public RoundRectLabelRenderer ()
		{
		}

		protected override void OnElementChanged (ElementChangedEventArgs<Label> e)
		{
			base.OnElementChanged (e);

			if (e.NewElement == null)
			{
				return;
			}

			if (Control != null)
			{
				Control.Invalidate ();
			}
		}

		protected override void OnElementPropertyChanged (object sender, System.ComponentModel.PropertyChangedEventArgs e)
		{
			base.OnElementPropertyChanged (sender, e);

//			var label = Element as RoundRectLabel;

			if (e.PropertyName == RoundRectLabel.TextProperty.PropertyName)
			{
				Control.Invalidate ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.BackgroundColorProperty.PropertyName)
			{
				Control.Invalidate ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.BorderColorProperty.PropertyName)
			{
				Control.Invalidate ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.BorderWidthProperty.PropertyName)
			{
				Control.Invalidate ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.CornerRadiusProperty.PropertyName)
			{
				Control.Invalidate ();
				return;
			}
			if (e.PropertyName == RoundRectLabel.HiddenValueProperty.PropertyName)
			{
				Control.Invalidate ();
				return;
			}
		}

		protected override void OnLayout (bool changed, int l, int t, int r, int b)
		{
			base.OnLayout (changed, l, t, r, b);

			var label = Element as RoundRectLabel;
			
			var background = new Android.Graphics.Drawables.GradientDrawable ();
			background.SetCornerRadius ((int)label.CornerRadius);
			background.SetStroke ((int)label.BorderWidth, label.BorderColor.ToAndroid ());
			background.SetColor (label.BackgroundColor.ToAndroid ());
			SetBackgroundColor (Android.Graphics.Color.Transparent);
			SetBackgroundDrawable (background);
		}
	}
}

great! How about UWP!