The CreateWindowEx function creates an overlapped, pop-up, or child window with an extended style; otherwise, this function is identical to the CreateWindow function. For more information about creating a window and for full descriptions of the other parameters of CreateWindowEx, see CreateWindow.
DWORD dwExStyle, // extended window style
LPCTSTR lpClassName, // pointer to registered class name
LPCTSTR lpWindowName, // pointer to window name
DWORD dwStyle, // window style
int x, // horizontal position of window
int y, // vertical position of window
int nWidth, // window width
int nHeight, // window height
HWND hWndParent, // handle to parent or owner window
HMENU hMenu, // handle to menu, or child-window identifier
HINSTANCE hInstance, // handle to application instance
LPVOID lpParam // pointer to window-creation data
Specifies the extended style of the window. This parameter can be one of the following values: Style Meaning
WS_EX_ACCEPTFILES Specifies that a window created with this style accepts drag-drop files.
WS_EX_APPWINDOW Forces a top-level window onto the taskbar when the window is visible.
WS_EX_CLIENTEDGE Specifies that a window has a border with a sunken edge.
WS_EX_CONTEXTHELP Includes a question mark in the title bar of the window. When the user clicks the question mark, the cursor changes to a question mark with a pointer. If the user then clicks a child window, the child receives a WM_HELP message. The child window should pass the message to the parent window procedure, which should call the WinHelp function using the HELP_WM_HELP command. The Help application displays a pop-up window that typically contains help for the child window.
WS_EX_CONTEXTHELP cannot be used with the WS_MAXIMIZEBOX or WS_MINIMIZEBOX styles.
WS_EX_CONTROLPARENT Allows the user to navigate among the child windows of the window by using the tab key.
WS_EX_DLGMODALFRAME Creates a window that has a double border; the window can, optionally, be created with a title bar by specifying the WS_CAPTION style in the dwStyle parameter.
WS_EX_LEFT Window has generic "left-aligned" properties. This is the default.
WS_EX_LEFTSCROLLBAR If the shell language is Hebrew, Arabic, or another language that supports reading order alignment, the vertical scroll bar (if present) is to the left of the client area. For other languages, the style is ignored and not treated as an error.
WS_EX_LTRREADING The window text is displayed using Left to Right reading-order properties. This is the default.
WS_EX_MDICHILD Creates an MDI child window.
WS_EX_NOPARENTNOTIFY Specifies that a child window created with this style does not send the WM_PARENTNOTIFY message to its parent window when it is created or destroyed.
WS_EX_OVERLAPPEDWINDOW Combines the WS_EX_CLIENTEDGE and WS_EX_WINDOWEDGE styles.
WS_EX_PALETTEWINDOW Combines the WS_EX_WINDOWEDGE, WS_EX_TOOLWINDOW, and WS_EX_TOPMOST styles.
WS_EX_RIGHT The window has generic "right-aligned" properties. This depends on the window class. This style has an effect only if the shell language is Hebrew, Arabic, or another language that supports reading order alignment; otherwise, the style is ignored and not treated as an error.
WS_EX_RIGHTSCROLLBAR Vertical scroll bar (if present) is to the right of the client area. This is the default.
WS_EX_RTLREADING If the shell language is Hebrew, Arabic, or another language that supports reading order alignment, the window text is displayed using Right to Left reading-order properties. For other languages, the style is ignored and not treated as an error.
WS_EX_STATICEDGE Creates a window with a three-dimensional border style intended to be used for items that do not accept user input.
WS_EX_TOOLWINDOW Creates a tool window; that is, a window intended to be used as a floating toolbar. A tool window has a title bar that is shorter than a normal title bar, and the window title is drawn using a smaller font. A tool window does not appear in the taskbar or in the dialog that appears when the user presses alt+tab. If a tool window has a system menu, its icon is not displayed on the title bar. However, you can display the system menu by right-clicking or by typing alt+space.
WS_EX_TOPMOST Specifies that a window created with this style should be placed above all non-topmost windows and should stay above them, even when the window is deactivated. To add or remove this style, use the SetWindowPos function.
WS_EX_TRANSPARENT Specifies that a window created with this style should not be painted until siblings beneath the window (that were created by the same thread) have been painted. The window appears transparent because the bits of underlying sibling windows have already been painted.
To achieve transparency without these restrictions, use theSetWindowRgn function.
WS_EX_WINDOWEDGE Specifies that a window has a border with a raised edge.
Using the WS_EX_RIGHT style for static or edit controls has the same effect as using the SS_RIGHT or ES_RIGHT style, respectively. Using this style with button controls has the same effect as using BS_RIGHT and BS_RIGHTBUTTON styles.
Pointer to a null-terminated string or is an integer atom. If lpClassName is an atom, it must be a global atom created by a previous call toGlobalAddAtom. The atom, a 16-bit value less than 0xC000, must be in the low-order word of lpClassName; the high-order word must be zero.
If lpClassName is a string, it specifies the window class name. The class name can be any name registered with the RegisterClassEx function or any of the predefined control-class names.
Pointer to a null-terminated string that specifies the window name.
If the window style specifies a title bar, the window title pointed to by lpWindowName is displayed in the title bar. When using CreateWindow to create controls, such as buttons, check boxes, and static controls, use lpWindowName to specify the text of the control.
Specifies the style of the window being created. This parameter can be a combination of the following window styles, plus the control styles indicated in the Remarks section. Style Meaning
WS_BORDER Creates a window that has a thin-line border.
WS_CAPTION Creates a window that has a title bar (includes the WS_BORDER style).
WS_CHILD Creates a child window. This style cannot be used with the WS_POPUP style.
WS_CHILDWINDOW Same as the WS_CHILD style.
WS_CLIPCHILDREN Excludes the area occupied by child windows when drawing occurs within the parent window. This style is used when creating the parent window.
WS_CLIPSIBLINGS Clips child windows relative to each other; that is, when a particular child window receives aWM_PAINT message, the WS_CLIPSIBLINGS style clips all other overlapping child windows out of the region of the child window to be updated. If WS_CLIPSIBLINGS is not specified and child windows overlap, it is possible, when drawing within the client area of a child window, to draw within the client area of a neighboring child window.
WS_DISABLED Creates a window that is initially disabled. A disabled window cannot receive input from the user.
WS_DLGFRAME Creates a window that has a border of a style typically used with dialog boxes. A window with this style cannot have a title bar.
WS_GROUP Specifies the first control of a group of controls. The group consists of this first control and all controls defined after it, up to the next control with the WS_GROUP style. The first control in each group usually has the WS_TABSTOP style so that the user can move from group to group. The user can subsequently change the keyboard focus from one control in the group to the next control in the group by using the direction keys.
WS_HSCROLL Creates a window that has a horizontal scroll bar.
WS_ICONIC Creates a window that is initially minimized. Same as the WS_MINIMIZE style.
WS_MAXIMIZE Creates a window that is initially maximized.
WS_MAXIMIZEBOX Creates a window that has a Maximize button. Cannot be combined with the WS_EX_CONTEXTHELP style. The WS_SYSMENU style must also be specified.
WS_MINIMIZE Creates a window that is initially minimized. Same as the WS_ICONIC style.
WS_MINIMIZEBOX Creates a window that has a Minimize button. Cannot be combined with the WS_EX_CONTEXTHELP style. The WS_SYSMENU style must also be specified.
WS_OVERLAPPED Creates an overlapped window. An overlapped window has a title bar and a border. Same as the WS_TILED style.
WS_OVERLAPPEDWINDOW Creates an overlapped window with the WS_OVERLAPPED, WS_CAPTION, WS_SYSMENU, WS_THICKFRAME, WS_MINIMIZEBOX, and WS_MAXIMIZEBOX styles. Same as the WS_TILEDWINDOW style.
WS_POPUP Creates a pop-up window. This style cannot be used with the WS_CHILD style.
WS_POPUPWINDOW Creates a pop-up window with WS_BORDER, WS_POPUP, and WS_SYSMENU styles. The WS_CAPTION and WS_POPUPWINDOW styles must be combined to make the window menu visible.
WS_SIZEBOX Creates a window that has a sizing border. Same as the WS_THICKFRAME style.
WS_SYSMENU Creates a window that has a window menu on its title bar. The WS_CAPTION style must also be specified.
WS_TABSTOP Specifies a control that can receive the keyboard focus when the user presses the tab key. Pressing the tab key changes the keyboard focus to the next control with the WS_TABSTOP style.
WS_THICKFRAME Creates a window that has a sizing border. Same as the WS_SIZEBOX style.
WS_TILED Creates an overlapped window. An overlapped window has a title bar and a border. Same as the WS_OVERLAPPED style.
WS_TILEDWINDOW Creates an overlapped window with the WS_OVERLAPPED, WS_CAPTION, WS_SYSMENU, WS_THICKFRAME, WS_MINIMIZEBOX, and WS_MAXIMIZEBOX styles. Same as the WS_OVERLAPPEDWINDOW style.
WS_VISIBLE Creates a window that is initially visible.
WS_VSCROLL Creates a window that has a vertical scroll bar.
Specifies the initial horizontal position of the window. For an overlapped or pop-up window, the x parameter is the initial x-coordinate of the window's upper-left corner, in screen coordinates. For a child window, x is the x-coordinate of the upper-left corner of the window relative to the upper-left corner of the parent window's client area.
If x is set to CW_USEDEFAULT, the system selects the default position for the window's upper-left corner and ignores the y parameter. CW_USEDEFAULT is valid only for overlapped windows; if it is specified for a pop-up or child window, the x and y parameters are set to zero.
Specifies the initial vertical position of the window. For an overlapped or pop-up window, the y parameter is the initial y-coordinate of the window's upper-left corner, in screen coordinates. For a child window, y is the initial y-coordinate of the upper-left corner of the child window relative to the upper-left corner of the parent window's client area. For a list box, y is the initial y-coordinate of the upper-left corner of the list box's client area relative to the upper-left corner of the parent window's client area.
If an overlapped window is created with the WS_VISIBLE style bit set and the x parameter is set to CW_USEDEFAULT, the system ignores the y parameter.
Specifies the width, in device units, of the window. For overlapped windows, nWidth is the window's width, in screen coordinates, or CW_USEDEFAULT. If nWidth is CW_USEDEFAULT, the system selects a default width and height for the window; the default width extends from the initial x-coordinates to the right edge of the screen; the default height extends from the initial y-coordinate to the top of the icon area. CW_USEDEFAULT is valid only for overlapped windows; if CW_USEDEFAULT is specified for a pop-up or child window, the nWidth and nHeight parameter are set to zero.
Specifies the height, in device units, of the window. For overlapped windows, nHeight is the window's height, in screen coordinates. If the nWidth parameter is set to CW_USEDEFAULT, the system ignores nHeight.
Handle to the parent or owner window of the window being created. To create a child window or an owned window, supply a valid window handle. This parameter is optional for pop-up windows.
Windows NT 5.0 and later: To create a message-only window, supply HWND_MESSAGE or a handle to an existing message-only window.
Handle to a menu, or specifies a child-window identifier, depending on the window style. For an overlapped or pop-up window, hMenu identifies the menu to be used with the window; it can be NULL if the class menu is to be used. For a child window, hMenu specifies the child-window identifier, an integer value used by a dialog box control to notify its parent about events. The application determines the child-window identifier; it must be unique for all child windows with the same parent window.
Handle to the instance of the module to be associated with the window.
A pointer to a value to be passed to the window through the CREATESTRUCT structure passed in the lParam parameter the WM_CREATE message. If an application calls CreateWindow to create a multiple document interface (MDI) client window, lpParam must point to a CLIENTCREATESTRUCT structure.
If the function succeeds, the return value is a handle to the new window.
If the function fails, the return value is NULL. To get extended error information, callGetLastError.
The CreateWindowEx function sends WM_NCCREATE, WM_NCCALCSIZE, and WM_CREATE messages to the window being created.
For information on controlling whether the Taskbar displays a button for the created window, seeVisibility of Taskbar Buttons.
The following predefined control classes can be specified in the lpClassName parameter. Note the corresponding control styles you can use in the dwStyle parameter.
BUTTON Designates a small rectangular child window that represents a button the user can click to turn it on or off. Button controls can be used alone or in groups, and they can either be labeled or appear without text. Button controls typically change appearance when the user clicks them. For more information, see Buttons.
For a table of the button styles you can specify in the dwStyle parameter, see Button Styles.
COMBOBOX Designates a control consisting of a list box and a selection field similar to an edit control. When using this style, an application should either display the list box at all times or enable a drop-down list box. If the list box is visible, typing characters into the selection field highlights the first list box entry that matches the characters typed. Conversely, selecting an item in the list box displays the selected text in the selection field. For more information, see Combo Boxes.
For a table of the combo box styles you can specify in the dwStyle parameter, see Combo Box Styles.
EDIT Designates a rectangular child window into which the user can type text from the keyboard. The user selects the control and gives it the keyboard focus by clicking it or moving to it by pressing the tab key. The user can type text when the edit control displays a flashing caret; use the mouse to move the cursor, select characters to be replaced, or position the cursor for inserting characters; or use the backspace key to delete characters. For more information, see Edit Controls.
For a table of the edit control styles you can specify in the dwStyle parameter, see Edit Control Styles.
LISTBOX Designates a list of character strings. Specify this control whenever an application must present a list of names, such as filenames, from which the user can choose. The user can select a string by clicking it. A selected string is highlighted, and a notification message is passed to the parent window. For more information, see List Boxes.
For a table of the list box styles you can specify in the dwStyle parameter, see List Box Styles.
MDICLIENT Designates an MDI client window. This window receives messages that control the MDI application's child windows. The recommended style bits are WS_CLIPCHILDREN and WS_CHILD. Specify the WS_HSCROLL and WS_VSCROLL styles to create an MDI client window that allows the user to scroll MDI child windows into view. For more information, see Multiple Document Interface.
RichEdit Designates a Rich Edit version 1.0 control. This window lets the user view and edit text with character and paragraph formatting, and can include embedded COM objects. For more information, see Rich Edit Controls.
For a table of the rich edit control styles you can specify in the dwStyle parameter, see Rich Edit Control Styles.
RICHEDIT_CLASS Designates a Rich Edit version 2.0 control. This controls let the user view and edit text with character and paragraph formatting, and can include embedded COM objects. For more information, see Rich Edit Controls.
For a table of the rich edit control styles you can specify in the dwStyle parameter, see Rich Edit Control Styles.
SCROLLBAR Designates a rectangle that contains a scroll box and has direction arrows at both ends. The scroll bar sends a notification message to its parent window whenever the user clicks the control. The parent window is responsible for updating the position of the scroll box, if necessary. For more information, see Scroll Bars.
For a table of the scroll bar control styles you can specify in the dwStyle parameter, see Scroll Bar Control Styles.
STATIC Designates a simple text field, box, or rectangle used to label, box, or separate other controls. Static controls take no input and provide no output. For more information, see Static Controls.
For a table of the static control styles you can specify in the dwStyle parameter, see Static Control Styles.
Windows 95: The system can support a maximum of 16,364 window handles.
Windows CE: Windows CE does not support stand alone menu bars. The hMenu parameter must be NULL, unless it is used as a child-window identifier.
Windows CE versions 2.0 and later support the following two extended window styles:
A top level window created with this style cannot be activated. If a child window has this style, tapping it will not cause its top-level parent to be activated. A window that has this style will receive stylus events, but neither it nor its child windows can get the focus.
A window created with this style does not show animated exploding and imploding rectangles, and does not have a button on the taskbar.
The following dwExStyle flags are not supported.
Windows CE 1.0 does not support the WS_EX_TOPMOST style. Versions 2.0 and later do.
The following dwStyle flags are not supported.
All windows implicitly have the WS_CLIPSIBLINGS and WS_CLIPCHILDREN styles.
Windows CE 1.0 does not support owned windows, except for dialog boxes. If the hwndParent parameter is not NULL, the window is implicitly given the WS_CHILD style.