1 files changed, 100 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/Interactivity/PropertyCondition.cs b/Xamarin.Forms.Core/Interactivity/PropertyCondition.cs
new file mode 100644
index 00000000..be37d48f
--- /dev/null
+++ b/Xamarin.Forms.Core/Interactivity/PropertyCondition.cs
@@ -0,0 +1,100 @@
+using System;
+using System.ComponentModel;
+using System.Reflection;
+using Xamarin.Forms.Xaml;
+
+namespace Xamarin.Forms
+{
+	public sealed class PropertyCondition : Condition, IValueProvider
+	{
+		readonly BindableProperty _stateProperty;
+
+		BindableProperty _property;
+		object _triggerValue;
+
+		public PropertyCondition()
+		{
+			_stateProperty = BindableProperty.CreateAttached("State", typeof(bool), typeof(DataTrigger), false, propertyChanged: OnStatePropertyChanged);
+		}
+
+		public BindableProperty Property
+		{
+			get { return _property; }
+			set
+			{
+				if (_property == value)
+					return;
+				if (IsSealed)
+					throw new InvalidOperationException("Can not change Property once the Trigger has been applied.");
+				_property = value;
+			}
+		}
+
+		public object Value
+		{
+			get { return _triggerValue; }
+			set
+			{
+				if (_triggerValue == value)
+					return;
+				if (IsSealed)
+					throw new InvalidOperationException("Can not change Value once the Trigger has been applied.");
+				_triggerValue = value;
+			}
+		}
+
+		object IValueProvider.ProvideValue(IServiceProvider serviceProvider)
+		{
+			var valueconverter = serviceProvider.GetService(typeof(IValueConverterProvider)) as IValueConverterProvider;
+			Func<MemberInfo> minforetriever = () => Property.DeclaringType.GetRuntimeProperty(Property.PropertyName);
+
+			object value = valueconverter.Convert(Value, Property.ReturnType, minforetriever, serviceProvider);
+			Value = value;
+			return this;
+		}
+
+		internal override bool GetState(BindableObject bindable)
+		{
+			return (bool)bindable.GetValue(_stateProperty);
+		}
+
+		internal override void SetUp(BindableObject bindable)
+		{
+			object newvalue = bindable.GetValue(Property);
+
+			bool newState = (newvalue == Value) || (newvalue != null && newvalue.Equals(Value));
+			bindable.SetValue(_stateProperty, newState);
+			bindable.PropertyChanged += OnAttachedObjectPropertyChanged;
+		}
+
+		internal override void TearDown(BindableObject bindable)
+		{
+			bindable.ClearValue(_stateProperty);
+			bindable.PropertyChanged -= OnAttachedObjectPropertyChanged;
+		}
+
+		void OnAttachedObjectPropertyChanged(object sender, PropertyChangedEventArgs e)
+		{
+			var bindable = (BindableObject)sender;
+			var oldState = (bool)bindable.GetValue(_stateProperty);
+
+			if (Property == null)
+				return;
+			if (e.PropertyName != Property.PropertyName)
+				return;
+			object newvalue = bindable.GetValue(Property);
+			bool newstate = (newvalue == Value) || (newvalue != null && newvalue.Equals(Value));
+			if (oldState != newstate)
+				bindable.SetValue(_stateProperty, newstate);
+		}
+
+		void OnStatePropertyChanged(BindableObject bindable, object oldValue, object newValue)
+		{
+			if ((bool)oldValue == (bool)newValue)
+				return;
+
+			if (ConditionChanged != null)
+				ConditionChanged(bindable, (bool)oldValue, (bool)newValue);
+		}
+	}
+}
+\ No newline at end of file