Public Property RelativeTo As FrameworkElement

Dim instance As UXPopup
Dim value As FrameworkElement
 
instance.RelativeTo = value
 
value = instance.RelativeTo

public FrameworkElement RelativeTo {get; set;}

public read-write property RelativeTo: FrameworkElement; 

public function get,set RelativeTo : FrameworkElement

public: __property FrameworkElement* get_RelativeTo();
public: __property void set_RelativeTo( 
   FrameworkElement* value
);

public:
property FrameworkElement^ RelativeTo {
   FrameworkElement^ get();
   void set (    FrameworkElement^ value);
}

<Grid x:Name="LayoutRoot">
    <Grid VerticalAlignment="Top" HorizontalAlignment="Left">
        <Intersoft:UXPopup PreferredPosition="TopRight" x:Name="MyPopup" RelativeTo="{Binding ElementName=MyButton}">
            <Grid Width="100" Height="100" Background="#FF8ECEFF">
                <TextBlock TextWrapping="Wrap" Text="Put your popup content here" Margin="4"/>
            </Grid>
        </Intersoft:UXPopup>
    </Grid>
    <Button Width="100" Content="Click Me" x:Name="MyButton" HorizontalAlignment="Center" VerticalAlignment="Center" Click="MyButton_Click"/>
</Grid>

private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
{
        this.MyPopup.IsOpen = !this.MyPopup.IsOpen;
}