| public RemoveValueChanged ( object component, EventHandler handler ) : void | ||
| component | object | |
| handler | EventHandler | |
| return | void | |
/// <summary>
/// Returns an observable sequence of property changed notifications from the
/// specified <paramref name="property"/> descriptor.
/// </summary>
/// <param name="property">The descriptor from which to create an observable sequence of changed notifications.</param>
/// <param name="source">The object to which the <paramref name="property"/> belongs.</param>
/// <returns>An observable sequence of property changed notifications.</returns>
/// <exception cref="ArgumentException">The specified property does not support change events.</exception>
public static IObservable <EventPattern <PropertyChangedEventArgs> > PropertyChanged(
this PropertyDescriptor property,
object source)
{
Contract.Requires(property != null);
Contract.Requires(source != null);
Contract.Ensures(Contract.Result <IObservable <EventPattern <PropertyChangedEventArgs> > >() != null);
if (!property.SupportsChangeEvents)
{
throw new ArgumentException(Errors.PropertyDoesNotSupportChangeEvents, "property");
}
return
(from e in Observable.FromEventPattern <EventHandler, EventArgs>(
handler => handler.Invoke,
handler => property.AddValueChanged(source, handler),
handler => property.RemoveValueChanged(source, handler))
select new EventPattern <PropertyChangedEventArgs>(
e.Sender,
e.EventArgs as PropertyChangedEventArgs ?? new PropertyChangedEventArgs(property.Name)));
}
/// <summary>
/// Unsubscribes the value changed event.
/// </summary>
/// <param name="descriptor">
/// The descriptor.
/// </param>
/// <param name="handler">
/// The handler.
/// </param>
protected void UnsubscribeValueChanged(PropertyDescriptor descriptor, EventHandler handler)
{
if (this.IsEnumerable)
{
var list = this.Instance as IEnumerable;
if (list == null)
{
throw new InvalidOperationException("Instance should be a list.");
}
foreach (var item in list)
{
descriptor.RemoveValueChanged(this.GetPropertyOwner(descriptor, item), handler);
}
}
else
{
descriptor.RemoveValueChanged(this.GetPropertyOwner(descriptor, this.Instance), handler);
}
}
