SetWindowPos (Compact 2013)


This function changes the size, position, and z-order of a child, pop-up, or top-level window. Child, pop-up, and top-level windows are ordered according to their appearance on the screen. The topmost window receives the highest rank and is the first window in the z-order.

BOOL SetWindowPos(
  HWND hWnd,
  HWND hWndInsertAfter,
  int X,
  int Y,
  int cx,
  int cy,
  UINT uFlags 


[in] Handle to the window.


[in] Handle to the window to precede the positioned window in the z-order. This parameter must be a window handle or one of the following values.




Places the window at the bottom of the z-order. If the hWnd parameter identifies a topmost window, the window loses its topmost status and is placed at the bottom of all other windows.


Places the window above all non-topmost windows and below all topmost windows. This flag has no effect when SWP_NOACTIVATE is set or if the window is already above all non-topmost windows.


Places the window at the top of the z-order.


Places the window above all non-topmost windows. The window maintains its topmost position even when it is deactivated.

For more information about how this parameter is used, see the Remarks section.


[in] Specifies the new position of the left side of the window, in client coordinates.


[in] Specifies the new position of the top of the window, in client coordinates.


[in] Specifies the new width of the window, in pixels.


[in] Specifies the new height of the window, in pixels.


[in] Specifies the window sizing and positioning flags. This parameter can be a combination of the following values.




Draws a frame (defined in the window's class description) around the window.


Causes the operating system to recalculate the size and position of the windows client area, even if the window size is not being changed. If this flag is not specified, the client area is recalculated only when the size or position of the window changes.


Hides the window.


Prevents the window from being activated. When this flag is not set, the window is activated and positioned according to the value of hWndInstertAfter and the setting of the SWP_NOZORDER flag. Otherwise, the window moves to the top of its current topmost status group.


This value is not supported.


Retains the current position (ignores the X and Y parameters).


Does not change the owner window's position in the z-order.




Retains the current size (ignores cx and cy).


Prevent change of z-order based on hWndInsertAfter.

The z-order can change with SWP_NOZORDER set if a top-level window which is not on top has SWP_NOACTIVATE unset. This results in moving the window to the top of its current topmost status group.


Displays the window.

Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.

If the specified window is not a toplevel window while hWndInsertAfter is set to either HWND_TOPMOST or HWND_NOTOPMOST and SWP_NOZORDER is not set, then the window will not be moved or resized despite the function returning TRUE.

If the specified window is a visible top-level window and the SWP_NOACTIVATE flag is not specified, this function activates the window. If the window is the currently active and the SWP_HIDEWINDOW flag is specified, the activation is passed on to another visible top-level window.

A window can be made a topmost window either by setting the hWndInsertAfter parameter to HWND_TOPMOST and ensuring that the SWP_NOZORDER flag is not set, or by setting a window's position in the z-order so that it is above any existing topmost windows. When a non-topmost window is made topmost, its owned windows are also made topmost. Its owners, however, are not changed.

If neither the SWP_NOACTIVATE nor SWP_NOZORDER flag is specified (that is, when the application requests that a window be simultaneously activated and its position in the z-order changed), the value specified in hWndInsertAfter is used only in the following circumstances.

  • Either the HWND_TOPMOST or HWND_NOTOPMOST flag is specified in hWndInsertAfter.
  • The window identified by hWnd is the active window.

When you set the SWP_FRAMECHANGED flag in the nFlags parameter to this function, Windows Embedded Compact redraws the entire non-client area of the window, which may change the size of the client area. This is the only way to get the non-client area to be recalculated and is typically used after you have changed the window style by calling SetWindowLong.

If you have changed certain window data using SetWindowLong, you must call SetWindowPos to have the changes take effect. Use the following combination for uFlags: SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED.

SetWindowPos always causes a WM_WINDOWPOSCHANGED message to be sent to the window. The flags passed in this message are exactly the same as those passed into the function. No other messages are sent by this function.

If an owned window was created with the WS_OVERLAPPED style, SetWindowPos uses the parent window coordinates to reposition it. If the owned window was created using the WS_POPUP style, it is repositioned using screen coordinates.

An application cannot activate an inactive window without also bringing it to the top of the z-order. Applications can change an activated window's position in the z-order without restrictions, or it can activate a window and then move it to the top of the topmost or non-topmost windows.

If a topmost window is repositioned to the bottom (HWND_BOTTOM) of the z-order or after any non-topmost window, it is no longer topmost. When a topmost window is made non-topmost, its owners and its owned windows are also made non-topmost windows.

A non-topmost window can own a topmost window, but the reverse cannot occur. Any window (for example, a dialog box) owned by a topmost window is itself made a topmost window, to ensure that all owned windows stay above their owner.

If an application is not in the foreground, and should be in the foreground, it must call the SetForegroundWindow function.



© 2016 Microsoft