Occurs before the editor's value is changed.
public event EditValueChangingEventHandler EditValueChanging
Public Event EditValueChanging As EditValueChangingEventHandler
The EditValueChanging event's data class is EditValueChangingEventArgs. The following properties provide information specific to this event:
|Handled||Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.|
|IsCancel||Gets or sets a value indicating whether the event should be canceled.|
|NewValue||Gets a new value to be assigned to the editor.|
|OldValue||Gets the current edit value, which should be replaced by the new value.|
|OriginalSource||Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.|
|RoutedEvent||Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.|
|Source||Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.|
The event data class exposes the following methods:
|InvokeEventHandler(Delegate, Object)||When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.|
|OnSetSource(Object)||When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.|
The EditValueChanging event is raised when the editor's value is about to be changed (a user types or deletes a character, chooses a value from a dropdown list, etc.). The potential new value is returned by the event parameter's NewValue property. The current value is returned by the OldValue property. To cancel posting EditValueChangingEventArgs.NewValue to BaseEdit.EditValue, set the EditValueChangingEventArgs.IsCancel and Handled properties to true.
After the editor's value has been changed, the BaseEdit.EditValueChanged event is fired.