property was already registered by 'FrameworkElement'

Question

I am writing two dependency properties and I keep getting the \"[Property] was already registered by \'FrameworkElement\'\" error in the design window of VS11. Here is a sn

Answer 1

The third parameter ownerType of the DependencyProperty.Register method must be the class that declares the property.

If your class is MyClass the declaration would have to look like this:

public class MyClass : DependencyObject
{
    public static readonly DependencyProperty IsEditingNumberProperty =
        DependencyProperty.Register(
            "IsEditingNumber", typeof(bool), typeof(MyClass), ...);

    // CLR wrapper
    public bool IsEditingNumber
    {
        get { return (bool)GetValue(IsEditingNumberProperty); }
        set { SetValue(IsEditingNumberProperty, value); }
    }
}