Article ID: 112181
Article Last Modified on 10/14/2003
APPLIES TO
- Microsoft Multimedia Viewer Publishing Toolkit 2.0
- Microsoft Multimedia Viewer Publishing Toolkit 2.0a
This article was previously published under Q112181
SUMMARY
This article describes how to change the style of a secondary window in a Viewer title. Changing the style of a secondary window allows you to remove the minimize button, remove the caption bar, and so on. You must write a dynamic-link library (DLL) in C to change the style of a secondary window in a Viewer title.
MORE INFORMATION
The style of Viewer's main window can be changed using the Windows SetWindowLong() function. The prototype for SetWindowLong() is
LONG SetWindowLong (HWND hwnd, int nOffset, LONG nVal)
where hwnd is the handle of the secondary window, nOffset is the offset of the value to change, and nVal is the new value for the offset. Further documentation for the SetWindowLong() function can be found in the documentation for the Windows 3.1 Software Development Kit (SDK).
Perform the following two steps to get the first parameter [which will be the handle (hwnd) to your secondary window]:
- Make sure that secondary window has the input focus. You can use the FocusWindow() Viewer command to accomplish this.
Use the Windows application programming interface (API) function GetParent() to extract the correct handle from the hwndContext variable. The hwndContext variable is documented on page 5-8 of the Microsoft Multimedia Viewer "Technical Reference."
NOTE
: hwndContext is a 32-bit value. Therefore, you will need to use the LOWORD() function to extract the 16-bit window handle. In your DLL, you should write the following function:
HWND FAR PASCAL __export GetSecondaryHandle (DWORD hwnd) { return GetParent (LOWORD(hwnd)); }
The second parameter, nOffset, should be set to -16 (which is the value of the Windows constant GWL_STYLE) to change the window style.
The possible values for the third parameter, nVal, are combinations of the following:
WS_CLIPSIBLINGS 0x04000000
WS_CLIPCHILDREN 0x02000000
WS_VISIBLE 0x10000000
WS_DISABLED 0x08000000
WS_MINIMIZE 0x20000000
WS_MAXIMIZE 0x01000000
WS_CAPTION 0x00C00000
WS_BORDER 0x00800000
WS_DLGFRAME 0x00400000
WS_VSCROLL 0x00200000
WS_HSCROLL 0x00100000
WS_SYSMENU 0x00080000
WS_THICKFRAME 0x00040000
WS_MINIMIZEBOX 0x00020000
WS_MAXIMIZEBOX 0x00010000
These values are combined simply by or'ing them together with the bitwise OR operator ("|"). Each call to SetWindowLong() completely replaces the previous styles for the window with the new styles specified in the nVal parameter.
By default, the main Viewer window has the styles WS_VISIBLE, WS_CLIPSIBLINGS, WS_CLIPCHILDREN, WS_CAPTION, WS_SYSMENU, WS_THICKFRAME, WS_MINIMIZEBOX, and WS_MAXIMIZEBOX (that is, nVal=0x16CF0000).
NOTE: Microsoft recommends that you always include the WS_VISIBLE, WS_CLIPSIBLINGS, and WS_CLIPCHILDREN styles in the new value. This means the value of nVal would always be at least 0x16000000.
To use SetWindowLong() and GetSecondaryHandle() from Viewer, these functions must be registered in the [CONFIG] section of the .MVP file as follows
RegisterRoutine ("user", "SetWindowLong", "uiU")
RegisterRoutine ("mydll", "GetSecondaryHandle()", "u=U")
where mydll is the name of your .DLL file.
SetWindowLong() can then be called from anywhere within the title with GetSecondaryHandle(hwndContext) as the first parameter, -16 as the second parameter, and the appropriate new style value in the third parameter.
To cause the main window frame to be redrawn immediately after the change to its style, you may need to call the Windows function SetWindowPos(), which is registered in the [CONFIG] section as follows:
RegisterRoutine ("user", "SetWindowPos", "uuiiiiu")
SetWindowPos() can then be called from anywhere within the title as follows:
SetWindowPos (GetSecondaryHandle (hwndContext), 0, 0, 0, 0, 0, 39)
NOTE: The SetWindowPos() call above is equivalent to the following function call using the Windows constants defined in the WINDOWS.H header file from the Windows SDK:
SetWindowPos (hwndApp, 0, 0, 0, 0, 0, SWP_DRAWFRAME |
SWP_NOMOVE |
SWP_NOSIZE |
SWP_NOZORDER)
Sample
To use a topic entry command to remove the maximize box from a secondary window called MyWindow, the SetWindowLong() call in the topic entry command code resembles the following:
FocusWindow (MyWindow);
SetWindowLong (GetSecondaryHandle (hwndContext), -16, 0x16CE0000);
SetWindowPos (GetSecondaryHandle (hwndContext), 0, 0, 0, 0, 0, 39);
Style Reference
The following list describes the styles mentioned above:
WS_BORDER Creates a window that has a border.
WS_CAPTION Creates a window that has a title bar (implies the
WS_BORDER style). This style cannot be used with the
WS_DLGFRAME style.
WS_CLIPCHILDREN Excludes the area occupied by child windows when drawing
within the parent window. Used when creating the parent
window.
WS_CLIPSIBLINGS Clips child windows relative to each other; that is, when
a particular child window receives a paint message, the
WS_CLIPSIBLINGS style clips all other overlapped 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.) For use with the
WS_CHILD style only.
WS_DISABLED Creates a window that is initially disabled.
WS_DLGFRAME Creates a window with a double border but no title.
WS_HSCROLL Creates a window that has a horizontal scroll bar.
WS_MAXIMIZE Creates a window of maximum size.
WS_MAXIMIZEBOX Creates a window that has a Maximize button.
WS_MINIMIZE Creates a window that is initially minimized. For use
with the WS_OVERLAPPED style only.
WS_MINIMIZEBOX Creates a window that has a Minimize button.
WS_SYSMENU Creates a window that has a System Menu box in its title
bar. Used only for windows with title bars.
WS_THICKFRAME Creates a window with a thick frame that can be used to
size the window.
WS_VISIBLE Creates a window that is initially visible. This applies
to overlapped, child, and pop-up windows. For overlapped
windows, the y parameter is used as a ShowWindow()
function parameter.
WS_VSCROLL Creates a window that has a vertical scroll bar.
NOTE: You can determine the current styles of the main Viewer window using the Spy utility that shipped with the Windows SDK. Choose Window from Spy's Window menu. Then position the cursor over the main Viewer window. Spy will display the style of the window in the last line of the Spy Window dialog box.
Additional query words: 2.00 2.00a
Keywords: KB112181
