NullableDatePickerRenderer.cs

using System;
using Xamarin.Forms.Platform.iOS;
using Xamarin.Forms;
using UIKit;
using System.Collections.Generic;
using NullableDatePicker.iOS;

[assembly: ExportRenderer(typeof(NullableDatePicker.Controls.NullableDatePicker), typeof(NullableDatePickerRenderer))]
namespace NullableDatePicker.iOS
{
	public class NullableDatePickerRenderer : DatePickerRenderer
	{
		protected override void OnElementChanged(ElementChangedEventArgs<DatePicker> e)
		{
			base.OnElementChanged(e);

			if (e.NewElement != null && this.Control != null)
			{
				this.AddClearButton();

				this.Control.BorderStyle = UITextBorderStyle.Line;
				Control.Layer.BorderColor = UIColor.LightGray.CGColor;
				Control.Layer.BorderWidth = 1;

				if (Device.Idiom == TargetIdiom.Tablet)
				{
					this.Control.Font = UIFont.SystemFontOfSize(25);
				}
			}

		}

		private void AddClearButton()
		{
			var originalToolbar = this.Control.InputAccessoryView as UIToolbar;

			if (originalToolbar != null && originalToolbar.Items.Length <= 2)
			{
				var clearButton = new UIBarButtonItem("Clear", UIBarButtonItemStyle.Plain, ((sender, ev) =>
				{
					NullableDatePicker.Controls.NullableDatePicker baseDatePicker = this.Element as NullableDatePicker.Controls.NullableDatePicker;
					this.Element.Unfocus();
					this.Element.Date = DateTime.Now;
					baseDatePicker.CleanDate();

				}));

				var newItems = new List<UIBarButtonItem>();
				foreach (var item in originalToolbar.Items)
				{
					newItems.Add(item);
				}

				newItems.Insert(0, clearButton);

				originalToolbar.Items = newItems.ToArray();
				originalToolbar.SetNeedsDisplay();
			}

		}
	}
}