Dependency Properties, change notification and setting values in the constructor
- by stefan.at.wpf
Hello,
I have a clas with 3 dependency properties A,B,C. The values of these properties are set by the constructor and every time one of the properties A, B or C changes, the method recalculate() is called. Now during execution of the constructor these method is called 3 times, because the 3 properties A, B, C are changed. Hoewever this isn't necessary as the method recalculate() can't do anything really useful without all 3 properties set. So what's the best way for property change notification but circumventing this change notification in the constructor? I thought about adding the property changed notification in the constructor, but then each object of the DPChangeSample class would always add more and more change notifications. Thanks for any hint!
class DPChangeSample : DependencyObject
{
public static DependencyProperty AProperty = DependencyProperty.Register("A", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged));
public static DependencyProperty BProperty = DependencyProperty.Register("B", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged));
public static DependencyProperty CProperty = DependencyProperty.Register("C", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged));
private static void propertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((DPChangeSample)d).recalculate();
}
private void recalculate()
{
// Using A, B, C do some cpu intensive caluclations
}
public DPChangeSample(int a, int b, int c)
{
SetValue(AProperty, a);
SetValue(BProperty, b);
SetValue(CProperty, c);
}
}
