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4/8/2010

This structure contains the window class attributes that are registered by the RegisterClassfunction.

Syntax

typedef struct _WNDCLASS {
  UINT 
style; 
  WNDPROC 
lpfnWndProc; 
  int 
cbClsExtra; 
  int 
cbWndExtra; 
  HANDLE 
hInstance; 
  HICON 
hIcon; 
  HCURSOR 
hCursor; 
  HBRUSH 
hbrBackground; 
  LPCTSTR 
lpszMenuName; 
  LPCTSTR 
lpszClassName; 
} WNDCLASS; 

Members

style

Specifies the class style(s). Styles can be combined by using the bitwise OR (|) operator. This member can be any combination of the following values.

Value Description

CS_DBLCLKS

Sends double-click messages to the window procedure when the user double-clicks the mouse while the cursor is within a window belonging to the class.

CS_HREDRAW

Redraws the entire window if a movement or size adjustment changes the width of the client area.

CS_NOCLOSE

Disables Closeon the windowmenu.

CS_PARENTDC

Sets the clipping region of the child window to that of the parent window so that the child can draw on the parent. A window with the CS_PARENTDC style bit receives a regular device context from the system's cache of device contexts. It does not give the child the parent's device context or device context settings. Specifying CS_PARENTDC enhances an application's performance.

CS_VREDRAW

Redraws the entire window if a movement or size adjustment changes the height of the client area.

lpfnWndProc

Long pointer to the window procedure. You must use the CallWindowProcfunction to call the window procedure. For more information, see WindowProc.

cbClsExtra

Specifies the number of extra bytes to allocate following the window-class structure. The system initializes the bytes to zero.

cbWndExtra

Specifies the number of extra bytes to allocate following the window instance. The system initializes the bytes to zero. If an application uses WNDCLASSto register a dialog box created by using the CLASSdirective in the resource file, the application must set cbWndExtraequal to the value obtained for cbWndExtrawhen the application calls the GetClassInfofunction on the system DIALOG class. This value is the number of extra bytes the OS requires for each dialog box.

hInstance

Handle to the instance that the window procedure of this class is within.

hIcon

Unsupported; set to NULL. An application must draw an icon whenever the user minimizes the application window.

hCursor

Handle to the class cursor. This member must be a handle to a cursor resource. If this member is NULL, an application must explicitly set the cursor shape whenever the mouse moves into the application's window.

hbrBackground

Handle to the class background brush. This member can be a handle to the physical brush to be used for painting the background, or it can be a color value. A color value must be one of the following standard system colors (the value 1 must be added to the chosen color). If a color value is given, you must convert it to one of the following HBRUSHtypes:

COLOR_ACTIVEBORDER

COLOR_HIGHLIGHTTEXT

COLOR_ACTIVECAPTION

COLOR_INACTIVEBORDER

COLOR_APPWORKSPACE

COLOR_INACTIVECAPTION

COLOR_BACKGROUND

COLOR_MENU

COLOR_BTNFACE

COLOR_MENUTEXT

COLOR_BTNSHADOW

COLOR_SCROLLBAR

COLOR_BTNTEXT

COLOR_WINDOW

COLOR_CAPTIONTEXT

COLOR_WINDOWFRAME

COLOR_GRAYTEXT

COLOR_WINDOWTEXT

COLOR_HIGHLIGHT

 

The system automatically deletes class background brushes when the class is freed. An application should not delete these brushes, because a class may be used by multiple instances of an application.

When this member is NULL, an application must paint its own background whenever it is requested to paint in its client area. To determine whether the background must be painted, an application can either process the WM_ERASEBKGND message or test the fErasemember of the PAINTSTRUCTstructure filled by the BeginPaintfunction.

lpszMenuName

Long pointer to a null-terminated character string that specifies the resource name of the class menu, as the name appears in the resource file. If you use an integer to identify the menu, use the MAKEINTRESOURCEmacro. If this member is NULL, windows belonging to this class have no default menu.

lpszClassName

Either a long pointer to a null-terminated string or an atom. If this member is an atom, it must be a global atom created by a previous call to the GlobalAddAtomfunction. The atom, a 16-bit value, must be in the low-order word of lpszClassName; the high-order word must be zero.

If lpszClassNameis a string, it specifies the window class name.

Remarks

The following members are restricted.

  • cbClsExtramust be a multiple of four.

  • cbWndExtramust be a multiple of four.

  • Unless you are using the Windows Embedded CE Iconcurs component, which supports mouse cursors on appropriate target platforms, the hCursormember must be set to NULL.

  • lpszMenuNameis not supported and must be NULL.

  • lpszClassNamemust be a string. Atoms are not supported.

  • In Windows CE 1.0, the stylemember can only be the CS_DBLCLKS value.

  • In Windows CE 2.0 and later, the stylemember can be the following values:

    • CS_DBLCLKS

    • CS_HREDRAW

    • CS_IME

    • CS_NOCLOSE

    • CS_PARENTDC

    • CS_VREDRAW

In Windows Embedded CE, all window classes are process global.

Note:
The technique of putting a class name and DLL in the registry and having a DLL automatically loaded is not supported.

Requirements

Header winuser.h
Windows Embedded CE Windows CE 1.0 and later
Windows Mobile Windows Mobile Version 5.0 and later

See Also