UITextField category and UIAppearance extensions

UITextFieldPlaceholderTextColorExtensions.cs

using Foundation;
using ObjCRuntime;
using UIKit;

namespace Categories
{
    [Category(typeof(UITextField)), Preserve]
    public static class UITextFieldPlaceholderTextColorExtensions
    {
        [Export("placeholderTextColor")]
        public static UIColor PlaceholderTextColor(this UITextField self) =>
            self.AttributedPlaceholder.GetAttribute(UIStringAttributeKey.ForegroundColor, 0, out _) as UIColor;

        [Export("setPlaceholderTextColor:")]
        public static void SetPlaceholderTextColor(this UITextField self, UIColor placeholderTextColor)
        {
            if (self.AttributedPlaceholder is null)
            {
                if (self.Placeholder is null)
                {
                    return;
                }

                self.AttributedPlaceholder = new NSAttributedString(self.Placeholder,
                    new NSDictionary(UIStringAttributeKey.ForegroundColor, placeholderTextColor));
            }
            else
            {
                var attributedString = new NSMutableAttributedString(self.AttributedPlaceholder);

                if (placeholderTextColor is null)
                {
                    attributedString.RemoveAttribute(UIStringAttributeKey.ForegroundColor,
                        new NSRange(0, self.AttributedPlaceholder.Length));
                }
                else
                {
                    attributedString.SetAttributes(
                        new NSDictionary(UIStringAttributeKey.ForegroundColor, placeholderTextColor),
                        new NSRange(0, self.AttributedPlaceholder.Length));
                }

                self.AttributedPlaceholder = attributedString;
            }
        }

        private static readonly Selector PlaceholderTextColorSetter = new Selector("setPlaceholderTextColor:");
        private static readonly Selector PlaceholderTextColorGetter = new Selector("placeholderTextColor");

        public static void SetPlaceholderTextColor(this UITextField.UITextFieldAppearance self,
            UIColor placeholderTextColor)
        {
            self.PerformSelector(PlaceholderTextColorSetter, placeholderTextColor);
        }

        public static UIColor GetPlaceholderTextColor(this UITextField.UITextFieldAppearance self)
        {
            var color = self.PerformSelector(PlaceholderTextColorGetter);
            return (UIColor) color;
        }
    }
}