I have derived my own class from a UpDownBase. Like so:

__gc public class MyNumericUpDown : public UpDownBase, ISupportInitialize
{...}

I created my own custom controls using my derived class. I go to build, and
I receive this error:
error C3141: 'System::ComponentModel::ISupportInitialize' : interfaces only
support public inheritance

I tried to add public in front of ISupportInitialize, but when I go to build
I will then get this error:
error C2259: 'MyNumericUpDown' : cannot instantiate abstract class

The above error occurs at the BeginInit() and EndInit() in
InitializeComponent, for my control:
__try_cast<System::ComponentModel::ISupportInitialize *  

For some reason it will not let the control be initialized!

Anybody have an ideas why I'm getting these build errors?

Thanks,