I have the following code to subscribe to property changed event for VisiblePosition property of Column class: 

DependencyPropertyDescriptor dpd = DependencyPropertyDescriptor.FromProperty(ColumnBase.VisiblePositionProperty, typeof(Column));

if (dpd != null)
{
   dpd.AddValueChanged(col, ColumnVisiblePositionChangedHandler);
}

Here is the definition of the ColumnVisiblePositionChangedHandler method:

static internal void ColumnVisiblePositionChangedHandler(object sender, EventArgs e)

The problem is I need to get the old value of the property. How do I do that?

Thanks,

wpf dependency-properties
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