You may not notice it, but when you work with Windows Forms, you are working with the System.Windows.Forms namespace. This namespace is included in the using directives in one of the files that holds the Form class. Most controls in .NET derive from the System.Windows.Forms.Control class. This class defines the basic functionality of the controls, which is why many properties and events in the controls you'll see are identical. Many of these classes are themselves base classes for other controls, as is the case with the Label and TextBoxBase classes in Figure 14-1.
Figure 14-1