RoutedPropertyChangedEventHandler

Below is a system defined delegate:

//Represents methods that will handle various routed events that //track property value changes.

public delegate void RoutedPropertyChangedEventHandler<T>(object sender, RoutedPropertyChangedEventArgs<T> e);

 

below is partial definition of RoutedPropertyChangedEventArgs<T>:

public class RoutedPropertyChangedEventArgs<T> : RoutedEventArgs

{

// Summary:

// Initializes a new instance of the System.Windows.RoutedPropertyChangedEventArgs<T>

// class, with provided old and new values.

//

// Parameters:

// oldValue:

// Previous value of the property, prior to the event being raised.

//

// newValue:

// Current value of the property at the time of the event.

public RoutedPropertyChangedEventArgs(T oldValue, T newValue);

…

}

 

e.g. Slider's ValueChanged event is of this type:

Slider s = new Slider();

s.ValueChanged += new System.Windows.RoutedPropertyChangedEventHandler<double>(s_ValueChanged);

 

static void s_ValueChanged(object sender, System.Windows.RoutedPropertyChangedEventArgs<double> e)

{

// both e.OldValue and e.NewValue are "double" type.

}