var WindowStyle:Longint; begin WindowStyle:=GetWindowLong(Form1.Handle, GWL_STYLE); WindowStyle:=WindowStyle or WS_Caption; SetWindowLong(Form1.Handle, GWL_STYLE, WindowStyle);END;
SetWindowLong The SetWindowLong function changes an attribute of the specified window. The function also sets the 32-bit (long) value at the specified offset into the extra window memory. Note This function has been superseded by the SetWindowLongPtr function. To write code that is compatible with both 32-bit and 64-bit versions of Windows, use SetWindowLongPtr. LONG SetWindowLong( HWND hWnd, // handle to window int nIndex, // offset of value to set LONG dwNewLong // new value ); Parameters hWnd [in] Handle to the window and, indirectly, the class to which the window belongs. Windows 95/98: The SetWindowLong function may fail if the window specified by the hWnd parameter does not belong to the same process as the calling thread. nIndex [in] Specifies the zero-based offset to the value to be set. Valid values are in the range zero through the number of bytes of extra window memory, minus 4; for example, if you specified 12 or more bytes of extra memory, a value of 8 would be an index to the third 32-bit integer. To set any other value, specify one of the following values. Value Action GWL_EXSTYLE Sets a new extended window style. For more information, see CreateWindowEx. GWL_STYLE Sets a new window style. GWL_WNDPROC Sets a new address for the window procedure. Windows NT/2000: You cannot change this attribute if the window does not belong to the same process as the calling thread.
GWL_HINSTANCE Sets a new application instance handle. GWL_ID Sets a new identifier of the window. GWL_USERDATA Sets the 32-bit value associated with the window. Each window has a corresponding 32-bit value intended for use by the application that created the window. This value is initially zero. The following values are also available when the hWnd parameter identifies a dialog box. Value Action DWL_DLGPROC Sets the new address of the dialog box procedure. DWL_MSGRESULT Sets the return value of a message processed in the dialog box procedure. DWL_USER Sets new extra information that is private to the application, such as handles or pointers. dwNewLong [in] Specifies the replacement value. Return Values If the function succeeds, the return value is the previous value of the specified 32-bit integer.If the function fails, the return value is zero. To get extended error information, call GetLastError. If the previous value of the specified 32-bit integer is zero, and the function succeeds, the return value is zero, but the function does not clear the last error information. This makes it difficult to determine success or failure. To deal with this, you should clear the last error information by calling SetLastError(0) before calling SetWindowLong. Then, function failure will be indicated by a return value of zero and a GetLastError result that is nonzero.Res Certain window data is cached, so changes you make using SetWindowLong will not take effect until you call the SetWindowPos function. Specifically, if you change any of the frame styles, you must call SetWindowPos with the SWP_FRAMECHANGED flag for the cache to be updated properly. If you use SetWindowLong with the GWL_WNDPROC index to replace the window procedure, the window procedure must conform to the guidelines specified in the description of the WindowProc callback function. If you use SetWindowLong with the DWL_MSGRESULT index to set the return value for a message processed by a dialog procedure, you should return TRUE directly afterwards. Otherwise, if you call any function that results in your dialog procedure receiving a window message, the nested window message could overwrite the return value you set using DWL_MSGRESULT. Calling SetWindowLong with the GWL_WNDPROC index creates a subclass of the window class used to create the window. An application can subclass a system class, but should not subclass a window class created by another process. The SetWindowLong function creates the window subclass by changing the window procedure associated with a particular window class, causing the system to call the new window procedure instead of the previous one. An application must pass any messages not processed by the new window procedure to the previous window procedure by calling CallWindowProc. This allows the application to create a chain of window procedures. Reserve extra window memory by specifying a nonzero value in the cbWndExtra member of the WNDCLASSEX structure used with the RegisterClassEx function. You must not call SetWindowLong with the GWL_HWNDPARENT index to change the parent of a child window. Instead, use the SetParent function.
例子：SetWindowLong(Handle, GWL_EXSTYLE, WS_EX_TOOLWINDOW or WS_EX_STATICEDGE); SetWindowPos(Handle, HWND_TOP, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE or SWP_FRAMECHANGED);
GWL_STYLE可以取的值：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. A window with this style cannot have a menu bar. 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 a WM_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. To change this after a window has been created, use EnableWindow. 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. You can turn this style on and off to change dialog box navigation. To change this style after a window has been created, use SetWindowLong.
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. You can turn this style on and off to change dialog box navigation. To change this style after a window has been created, use SetWindowLong.
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. This style can be turned on and off by using ShowWindow or SetWindowPos.
WS_VSCROLL Creates a window that has a vertical scroll bar.
WindowStyle:Longint;
begin
WindowStyle:=GetWindowLong(Form1.Handle, GWL_STYLE);
WindowStyle:=WindowStyle or WS_Caption; SetWindowLong(Form1.Handle, GWL_STYLE, WindowStyle);END;
The SetWindowLong function changes an attribute of the specified window. The function also sets the 32-bit (long) value at the specified offset into the extra window memory. Note This function has been superseded by the SetWindowLongPtr function. To write code that is compatible with both 32-bit and 64-bit versions of Windows, use SetWindowLongPtr. LONG SetWindowLong(
HWND hWnd, // handle to window
int nIndex, // offset of value to set
LONG dwNewLong // new value
);
Parameters
hWnd
[in] Handle to the window and, indirectly, the class to which the window belongs.
Windows 95/98: The SetWindowLong function may fail if the window specified by the hWnd parameter does not belong to the same process as the calling thread. nIndex
[in] Specifies the zero-based offset to the value to be set. Valid values are in the range zero through the number of bytes of extra window memory, minus 4; for example, if you specified 12 or more bytes of extra memory, a value of 8 would be an index to the third 32-bit integer. To set any other value, specify one of the following values. Value Action
GWL_EXSTYLE Sets a new extended window style. For more information, see CreateWindowEx.
GWL_STYLE Sets a new window style.
GWL_WNDPROC Sets a new address for the window procedure.
Windows NT/2000: You cannot change this attribute if the window does not belong to the same process as the calling thread.
GWL_HINSTANCE Sets a new application instance handle.
GWL_ID Sets a new identifier of the window.
GWL_USERDATA Sets the 32-bit value associated with the window. Each window has a corresponding 32-bit value intended for use by the application that created the window. This value is initially zero.
The following values are also available when the hWnd parameter identifies a dialog box. Value Action
DWL_DLGPROC Sets the new address of the dialog box procedure.
DWL_MSGRESULT Sets the return value of a message processed in the dialog box procedure.
DWL_USER Sets new extra information that is private to the application, such as handles or pointers. dwNewLong
[in] Specifies the replacement value.
Return Values
If the function succeeds, the return value is the previous value of the specified 32-bit integer.If the function fails, the return value is zero. To get extended error information, call GetLastError. If the previous value of the specified 32-bit integer is zero, and the function succeeds, the return value is zero, but the function does not clear the last error information. This makes it difficult to determine success or failure. To deal with this, you should clear the last error information by calling SetLastError(0) before calling SetWindowLong. Then, function failure will be indicated by a return value of zero and a GetLastError result that is nonzero.Res
Certain window data is cached, so changes you make using SetWindowLong will not take effect until you call the SetWindowPos function. Specifically, if you change any of the frame styles, you must call SetWindowPos with the SWP_FRAMECHANGED flag for the cache to be updated properly. If you use SetWindowLong with the GWL_WNDPROC index to replace the window procedure, the window procedure must conform to the guidelines specified in the description of the WindowProc callback function. If you use SetWindowLong with the DWL_MSGRESULT index to set the return value for a message processed by a dialog procedure, you should return TRUE directly afterwards. Otherwise, if you call any function that results in your dialog procedure receiving a window message, the nested window message could overwrite the return value you set using DWL_MSGRESULT. Calling SetWindowLong with the GWL_WNDPROC index creates a subclass of the window class used to create the window. An application can subclass a system class, but should not subclass a window class created by another process. The SetWindowLong function creates the window subclass by changing the window procedure associated with a particular window class, causing the system to call the new window procedure instead of the previous one. An application must pass any messages not processed by the new window procedure to the previous window procedure by calling CallWindowProc. This allows the application to create a chain of window procedures. Reserve extra window memory by specifying a nonzero value in the cbWndExtra member of the WNDCLASSEX structure used with the RegisterClassEx function. You must not call SetWindowLong with the GWL_HWNDPARENT index to change the parent of a child window. Instead, use the SetParent function.
SetWindowPos(Handle, HWND_TOP, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE or SWP_FRAMECHANGED);
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. A window with this style cannot have a menu bar. 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 a WM_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. To change this after a window has been created, use EnableWindow.
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.
You can turn this style on and off to change dialog box navigation. To change this style after a window has been created, use SetWindowLong.
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.
You can turn this style on and off to change dialog box navigation. To change this style after a window has been created, use SetWindowLong.
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.
This style can be turned on and off by using ShowWindow or SetWindowPos.
WS_VSCROLL Creates a window that has a vertical scroll bar.