I am creating an application that will have multiple "panes". When an option is selected, the panel for that option will be placed on the form.

What's the best way for me to design a hierarchy of user controls all based off a single base control? I would really prefer to do it visually. If I do it in code, I can base each one off of a base class, but doing everything in code is tedious and painstaking.

If I design the panes visually, I don't have the inheritance I want. If Implement an interface, I'm assured of getting all the members needed, but then I lose other members I need on the panel:

private void AddPane()
{
    IPanel oControl;

    switch (sItemKey)
    { 
        case "ship_items":
            oControl = new crlShipItems();
            break;

        case "sview_inv":
            break;

        case "sreports":
            break;

    }

    this.Controls.Add(oControl);
    oControl.Top = iTop;
    oControl.Left = iLeft;
    oControl.Setup();
}

This doesn't compile because there is no Top or Left in the interface.

What's the right way to do this?