' Adds a property to this designer's control at design time 
' that indicates the outline color to use.
' The DesignOnlyAttribute ensures that the OutlineColor
' property is not serialized by the designer.
Protected Overrides Sub PreFilterProperties(ByVal properties As System.Collections.IDictionary)
    Dim pd As PropertyDescriptor = TypeDescriptor.CreateProperty( _
    GetType(ExampleControlDesigner), _
    "OutlineColor", _
    GetType(System.Drawing.Color), _
    New Attribute() {New DesignOnlyAttribute(True)})

    properties.Add("OutlineColor", pd)
End Sub

// Adds a property to this designer's control at design time 
// that indicates the outline color to use. 
// The DesignOnlyAttribute ensures that the OutlineColor
// property is not serialized by the designer.
protected override void PreFilterProperties(System.Collections.IDictionary properties)
{
    PropertyDescriptor pd = TypeDescriptor.CreateProperty(
        typeof(ExampleControlDesigner), 
        "OutlineColor",
        typeof(System.Drawing.Color),
        new Attribute[] { new DesignOnlyAttribute(true) });

    properties.Add("OutlineColor", pd);
}

protected:
   [ReflectionPermission(SecurityAction::Demand, Flags=ReflectionPermissionFlag::MemberAccess)]
   virtual void PreFilterProperties( System::Collections::IDictionary^ properties ) override
   {
      properties->Add( "OutlineColor", TypeDescriptor::CreateProperty( TestControlDesigner::typeid, "OutlineColor", System::Drawing::Color::typeid, nullptr ) );
   }