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using System;
using System.ComponentModel;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls.Primitives;
#if WINDOWS_UWP
namespace Xamarin.Forms.Platform.UWP
#else
namespace Xamarin.Forms.Platform.WinRT
#endif
{
public class SliderRenderer : ViewRenderer<Slider, Windows.UI.Xaml.Controls.Slider>
{
protected override void OnElementChanged(ElementChangedEventArgs<Slider> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
if (Control == null)
{
var slider = new Windows.UI.Xaml.Controls.Slider();
SetNativeControl(slider);
slider.ValueChanged += OnNativeValueCHanged;
// Even when using Center/CenterAndExpand, a Slider has an oddity where it looks
// off-center in its layout by a smidge. The default templates are slightly different
// between 8.1/UWP; the 8.1 rows are 17/Auto/32 and UWP are 18/Auto/18. The value of
// the hardcoded 8.1 rows adds up to 49 (when halved is 24.5) and UWP are 36 (18). Using
// a difference of about 6 pixels to correct this oddity seems to make them both center
// more correctly.
//
// The VerticalAlignment needs to be set as well since a control would not actually be
// centered if a larger HeightRequest is set.
if (Element.VerticalOptions.Alignment == LayoutAlignment.Center && Control.Orientation == Windows.UI.Xaml.Controls.Orientation.Horizontal)
{
Control.VerticalAlignment = VerticalAlignment.Center;
#if WINDOWS_UWP
slider.Margin = new Windows.UI.Xaml.Thickness(0, 7, 0, 0);
#else
slider.Margin = new Windows.UI.Xaml.Thickness(0, 13, 0, 0);
#endif
}
}
double stepping = Math.Min((e.NewElement.Maximum - e.NewElement.Minimum) / 10, 1);
Control.StepFrequency = stepping;
Control.SmallChange = stepping;
Control.Minimum = e.NewElement.Minimum;
Control.Maximum = e.NewElement.Maximum;
Control.Value = e.NewElement.Value;
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == Slider.MinimumProperty.PropertyName)
Control.Minimum = Element.Minimum;
else if (e.PropertyName == Slider.MaximumProperty.PropertyName)
Control.Maximum = Element.Maximum;
else if (e.PropertyName == Slider.ValueProperty.PropertyName)
{
if (Control.Value != Element.Value)
Control.Value = Element.Value;
}
}
void OnNativeValueCHanged(object sender, RangeBaseValueChangedEventArgs e)
{
((IElementController)Element).SetValueFromRenderer(Slider.ValueProperty, e.NewValue);
}
}
}
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