public Binding <TSource, TTarget> ObserveSourceEvent(UpdateTriggerMode mode = UpdateTriggerMode.PropertyChanged)
{
switch (mode)
{
case UpdateTriggerMode.LostFocus:
return(ObserveSourceEvent <View.FocusChangeEventArgs>("FocusChange"));
case UpdateTriggerMode.PropertyChanged:
return(CheckControlSource());
}
return(this);
}
public Binding <TSource, TTarget> ObserveTargetEvent(UpdateTriggerMode mode)
{
switch (mode)
{
case UpdateTriggerMode.LostFocus:
throw new ArgumentException(
"UpdateTriggerMode.LostFocus is only supported in Android at this time",
nameof(mode));
case UpdateTriggerMode.PropertyChanged:
return(CheckControlTarget());
}
return(this);
}
/// <summary>
/// Define when the binding should be evaluated when the bound target object
/// is a control. Because Xamarin controls are not DependencyObjects, the
/// bound property will not automatically update the binding attached to it. Instead,
/// use this method to define which of the control's events should be observed.
/// </summary>
/// <param name="mode">Defines the binding's update mode. Use
/// <see cref="UpdateTriggerMode.LostFocus"/> to update the binding when
/// the source control loses the focus. You can also use
/// <see cref="UpdateTriggerMode.PropertyChanged"/> to update the binding
/// when the source control's property changes.
/// NOTE: At this time the PropertyChanged mode is inactive on iOS. Use
/// <see cref="ObserveTargetEvent(string)"/> instead.
/// </param>
/// <returns>The Binding instance.</returns>
/// <exception cref="InvalidOperationException">When this method is called
/// on a OneTime or a OneWay binding. This exception can
/// also be thrown when the source object is null or has already been
/// garbage collected before this method is called.</exception>
public Binding <TSource, TTarget> UpdateTargetTrigger(UpdateTriggerMode mode)
{
return(ObserveTargetEvent(mode));
}
