private protected virtual void ExecuteChangeText(WriteableChangeTextOperation operation)
{
Node ParentNode = operation.ParentNode;
string PropertyName = operation.PropertyName;
string NewText = operation.NewText;
IWriteableNodeState State = (IWriteableNodeState)GetState(ParentNode);
Debug.Assert(State != null);
Debug.Assert(State.ValuePropertyTypeTable.ContainsKey(PropertyName));
Debug.Assert(State.ValuePropertyTypeTable[PropertyName] == Constants.ValuePropertyType.String);
string OldText = NodeTreeHelper.GetString(State.Node, PropertyName);
Debug.Assert(OldText != null);
NodeTreeHelper.SetString(State.Node, PropertyName, NewText);
operation.Update(State, OldText);
NotifyTextChanged(operation);
}