The CommonDialog class represents a component that provides a standard interface for common functionality required by Windows Forms applications. This figure shows the complete set of Windows Forms classes derived from the Dialog class. | Components The Component class represents an object that is marshaled by reference and can exist within a container. This figure shows the complete set of Windows Forms classes derived from the class. Common dialogs The CommonDialog class represents a component that provides a standard interface for common functionality required by Windows Forms applications. This figure shows the complete set of Windows Forms classes derived from the .