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                           About Control Windows
 
This topic describes the functions that allow you to use control windows in
your applications. You should also be familiar with the following topics:
 
    ◄MS OS/2 Resource Compiler►
    ◄Frame windows►
    ◄Messages and message queues►
 
Control windows are predefined window classes that applications use for
input and output. Control windows are typically used as part of a dialog
window and are defined in the dialog template. Applications can also create
control windows by calling the WinCreateWindow function with the appropriate
window-class specification. The following control-window classes are
predefined in MS OS/2:
 
Control      Description
────────────────────────────────────────────────────────────────────────────
Button       Buttons or boxes that the user selects by clicking or using the
             keyboard. Several button types are available, including push
             buttons, radio buttons, and check boxes.
 
Entry field  A single line of text that the user can edit.
 
Static       Text, icons, or bitmaps that do not respond to user input.
 
List box     A window containing a list of items, usually text strings, from
             which the user may scroll and make selections.
 
Menu         A list of items, either text or bitmaps. The items in a menu
             may be displayed horizontally across the top of a frame window,
             as in a menu bar, or vertically, in a menu. Menus typically
             provide the command interface for an application.
 
Scroll bar   A bar that allows a user to scroll the contents of a window.
             Scroll-bar controls contain directional arrows and an
             absolute-position indicator called the slider.
 
Title bar    A title or caption displayed across the top of a frame window.
             They can be used by a user to move the window, by dragging the
             title-bar control.
 
Control-Window Features
 
Control windows are always owned by other windows, usually dialog windows or
application frame windows. The ownership relationship is important because a
control window sends notification messages to its owner whenever an action
occurs in the control window. A control-window position is also expressed in
the coordinate space of its owner.
 
Control windows are like other predefined window classes in that they
respond to standard window management messages and functions, such as the
WinSetWindowText and WinShowWindow functions.
 
Control windows are usually painted synchronously. This means that a control
window is redrawn as soon as any part of it becomes invalid.
 
All control windows have a window ID. This ID is set either in a dialog
template or when the control is created by the WinCreateWindow function. The
ID is used when the control window sends notification messages to its owner.
Care must be taken to make sure that the control ID for a particular window
is not duplicated. Note that the control-window ID should not be the same as
the command ID associated with individual menu items.
 
All control-window classes have a set of specific messages that they send
and receive.
 
 
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