'宣言 Public MustInherit Class UpcBaseBuilder (Of TControl As UpcBase, TBuilder As UpcBaseBuilder(Of TControl,TBuilder)) Inherits BarcodeBaseBuilder(Of TControl,TBuilder)
public abstract class UpcBaseBuilder<TControl,TBuilder> : BarcodeBaseBuilder<TControl,TBuilder> where TControl: UpcBase where TBuilder: UpcBaseBuilder<TControl,TBuilder>