A control is a programming entity that has a graphical component. A control sits on a form and interacts with the user, providing information and possibly allowing the user to manipulate it. Text boxes, labels, buttons, scroll bars, drop-down lists, menu items, toolstrips, and just about everything else that you can see and interact with in a Windows application is a control.
Controls are an extremely important part of any interactive application. They give information to the user (Label, ToolTip, TreeView, PictureBox) and organize the information so that it's easier to understand (GroupBox, Panel, TabControl). They enable the user to enter data (TextBox, RichTextBox, ComboBox, MonthCalendar), select options (RadioButton, CheckBox, ListBox), tell the application to take action (Button, MenuStrip, ContextMenuStrip), and interact with objects outside of the application (OpenFileDialog, SaveFileDialog, PrintDocument, PrintPreviewDialog). Some controls also provide support for other controls (ImageList, ToolTip, ContextMenuStrip, ErrorProvider).
This chapter provides only a very brief description of the standard Windows Forms controls together with some tips that can help you decide which control to use for different purposes. Appendix G, "Windows Forms Controls and Components," covers the controls in much greater detail, describing each control's most useful properties, methods, and events.
Figure 8-1 shows the Visual Basic ...