Delphi抯 components reside in two class hierarchies called the Visual Component Library (VCL) and the Component Library for Cross Platform (CLX). The following figure shows the relationship of selected classes that make up the VCL. The CLX hierarchy is similar to the VCL but Windows controls are called widgets (therefore TWinControl is called TWidgetControl, for example), and there are other differences. For a more detailed discussion of class hierarchies and the inheritance relationships among classes, see Object-oriented programming for component writers For an overview of how CLX differs from the VCL, see
CLX versus VCL and refer to the CLX online reference for details on the components.The TComponent class is the shared ancestor of every component in the VCL and CLX. TComponent provides the minimal properties and events necessary for a component to work in Delphi. The various branches of the library provide other, more specialized capabilities.When you create a component, you add to the VCL or CLX by deriving a new class from one of the existing class types in the hierarchy.
CLX versus VCL and refer to the CLX online reference for details on the components.The TComponent class is the shared ancestor of every component in the VCL and CLX. TComponent provides the minimal properties and events necessary for a component to work in Delphi. The various branches of the library provide other, more specialized capabilities.When you create a component, you add to the VCL or CLX by deriving a new class from one of the existing class types in the hierarchy.
cross-platform component library (CLX)