DomainPropertyValueHandler<TElement,TValue>.OnValueChanging Method
Definition
Important
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Called when property value is about to change.
protected:
virtual void OnValueChanging(TElement element, TValue oldValue, TValue newValue);protected virtual void OnValueChanging (TElement element, TValue oldValue, TValue newValue);abstract member OnValueChanging : 'Element * 'Value * 'Value -> unit
override this.OnValueChanging : 'Element * 'Value * 'Value -> unitProtected Overridable Sub OnValueChanging (element As TElement, oldValue As TValue, newValue As TValue)Parameters
- element
- TElement
Element which owns the property.
- oldValue
- TValue
Old value of the property.
- newValue
- TValue
New value of the property.
Examples
protected override void OnValueChanging(ElementClassType element, FieldType oldValue, FieldType newValue) { // call the base class implementation first base.OnValueChanging(element, oldValue, newValue); if (element.Store.InUndoRedoOrRollback) { // your undo/redo only code goes here // you cannot make model changes here. // You can only change out-of-model state } else { // your non-undo/redo only code goes here // All your model changes should be done here. // You should not make any out-of-model state changes // here because it will not be in sync after undo/redo } // your other code goes here // you cannot make model changes here. You can only change // out-of-model state. }