Xamarin.Forms.Platform.iOS/Renderers/StepperRenderer.cs


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using System;
using System.Drawing;
using System.ComponentModel;
#if __UNIFIED__
using UIKit;

#else
using MonoTouch.UIKit;
#endif

namespace Xamarin.Forms.Platform.iOS
{
	public class StepperRenderer : ViewRenderer<Stepper, UIStepper>
	{
		protected override void Dispose(bool disposing)
		{
			if (Control != null)
				Control.ValueChanged -= OnValueChanged;

			base.Dispose(disposing);
		}

		protected override void OnElementChanged(ElementChangedEventArgs<Stepper> e)
		{
			if (e.NewElement != null)
			{
				if (Control == null)
				{
					SetNativeControl(new UIStepper(RectangleF.Empty));
					Control.ValueChanged += OnValueChanged;
				}

				UpdateMinimum();
				UpdateMaximum();
				UpdateValue();
				UpdateIncrement();
			}

			base.OnElementChanged(e);
		}

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

			if (e.PropertyName == Stepper.MinimumProperty.PropertyName)
				UpdateMinimum();
			else if (e.PropertyName == Stepper.MaximumProperty.PropertyName)
				UpdateMaximum();
			else if (e.PropertyName == Stepper.ValueProperty.PropertyName)
				UpdateValue();
			else if (e.PropertyName == Stepper.IncrementProperty.PropertyName)
				UpdateIncrement();
		}

		void OnValueChanged(object sender, EventArgs e)
		{
			((IElementController)Element).SetValueFromRenderer(Stepper.ValueProperty, Control.Value);
		}

		void UpdateIncrement()
		{
			Control.StepValue = Element.Increment;
		}

		void UpdateMaximum()
		{
			Control.MaximumValue = Element.Maximum;
		}

		void UpdateMinimum()
		{
			Control.MinimumValue = Element.Minimum;
		}

		void UpdateValue()
		{
			if (Control.Value != Element.Value)
				Control.Value = Element.Value;
		}
	}
}