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using System.Collections.Generic;
namespace Xamarin.Forms
{
internal sealed class MultiCondition : Condition
{
readonly BindableProperty _aggregatedStateProperty;
public MultiCondition()
{
_aggregatedStateProperty = BindableProperty.CreateAttached("AggregatedState", typeof(bool), typeof(MultiCondition), false, propertyChanged: OnAggregatedStatePropertyChanged);
Conditions = new TriggerBase.SealedList<Condition>();
}
public IList<Condition> Conditions { get; }
internal override bool GetState(BindableObject bindable)
{
return (bool)bindable.GetValue(_aggregatedStateProperty);
}
internal override void OnSealed()
{
((TriggerBase.SealedList<Condition>)Conditions).IsReadOnly = true;
foreach (Condition condition in Conditions)
condition.ConditionChanged = OnConditionChanged;
}
internal override void SetUp(BindableObject bindable)
{
foreach (Condition condition in Conditions)
condition.SetUp(bindable);
}
internal override void TearDown(BindableObject bindable)
{
foreach (Condition condition in Conditions)
condition.TearDown(bindable);
}
void OnAggregatedStatePropertyChanged(BindableObject bindable, object oldValue, object newValue)
{
if ((bool)oldValue == (bool)newValue)
return;
if (ConditionChanged != null)
ConditionChanged(bindable, (bool)oldValue, (bool)newValue);
}
void OnConditionChanged(BindableObject bindable, bool oldValue, bool newValue)
{
var oldState = (bool)bindable.GetValue(_aggregatedStateProperty);
var newState = true;
foreach (Condition condition in Conditions)
{
if (!condition.GetState(bindable))
{
newState = false;
break;
}
}
if (newState != oldState)
bindable.SetValue(_aggregatedStateProperty, newState);
}
}
}
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