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Why is the method Control.ChangeVisualState virtual *and* internal?

Posted By:      Posted Date: October 28, 2010    Points: 0   Category :WPF

I'm currently implementing a custo

m DatePicker (because the standard one eliminates the time portion of DateTime) and came across the internal virtual method ChangeVisualState of Control.

E.g. the standard DatePicker overrides the ChangeVisualState method the following way:

internal override void ChangeVisualState(bool useTransitions)
    if (!base.IsEnabled)
        VisualStates.GoToState(this, useTransitions, new string[] { "Disabled", "Normal" });

Why is the method Control.ChangeVisualState internal?
It seems like a central and important spot for changing visual states, so what's the point of making it internal?

How can I define the same behavior in my derived class of Control, without being able to override this internal method of the framework?


Additionally, why is the method Control.OnVisualStatePropertyChanged internal as well?
Does this all mean that usage of visual states is reserved for Microsoft, or did I miss something?



Kasimier Buchcik

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