The System.Windows.Forms namespace contains classes for creating Windows-based applications that take full advantage of the rich user interface features available in the Microsoft Windows operating system.

The classes in this namespace can be grouped into the following categories:

• Control, User Control, and Form. Most classes within the System.Windows.Forms namespace derive from the Control class. The Control class provides the base functionality for all controls that are displayed on a Form. The Form class represents a window within an application. This includes dialog boxes, modeless windows, and Multiple Document Interface (MDI) client and parent windows. To create a custom control that is a composite of other controls, use the UserControl class.
• Controls. The System.Windows.Forms namespace provides a variety of control classes that allow you to create rich user interfaces. Some controls are designed for data entry within the application, such as TextBox and ComboBox controls. Other controls display application data, such as Label and ListView. The namespace also provides controls for invoking commands within the application, such as Button and ToolBar. In addition, the PropertyGrid control can be used to create your own Windows Forms designer that displays the designer-visible properties of the controls.
• Components. In addition to controls, the System.Windows.Forms namespace provides other classes that do not derive from the Control class but still provide visual features to a Windows-based application. Some classes, such as ToolTip and ErrorProvider, extend the capabilities or provide information to the user. Other classes, such as Menu, MenuItem, and ContextMenu, provide the ability display menus to the user to invoke commands within an application. The Help and HelpProvider classes enable you to display help information to the user of your applications.
• Common Dialog Boxes. Windows provides a number of common dialog boxes that can be used to give your application a consistent user interface when performing tasks such as opening and saving files, manipulating the font or text color, or printing. The OpenFileDialog and SaveFileDialog classes provide the functionality to display a dialog box that allows the user to browse to and enter the name of a file to open or save. The FontDialog class displays a dialog box to change elements of the Font object used by your application. The PageSetupDialog, PrintPreviewDialog, and PrintDialog classes display dialog boxes that allow the user to control aspects of printing documents. For more information on printing from a Windows-based application, see the System.Drawing.Printing namespace. In addition to the common dialog boxes, the System.Windows.Forms namespace provides the MessageBox class for displaying a message box that can display and retrieve data from the user.

There are a number of classes within the System.Windows.Forms namespace that provide support to the classes mentioned in the preceding summary. Example of the supporting classes are enumerations, event argument classes, and delegates used by events within controls and components.

Note   To make your Windows Forms application support Windows XP visual styles, be sure to set the FlatStyle property of your controls to FlatStyle.System and include a manifest with your executable. A manifest is an XML file that is included either as a resource within your application executable or as a seperate file that resides in the same directory as the executable file. For an example of a manifest, see the Example section for the FlatStyle enumeration. For more information about using the visual styles available in Windows XP, see the Using Windows XP Visual Styles in the User Interface Design and Development section of the MSDN Library.

Namespace hierarchy

Classes