CTabPage

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CTabPage

Creates a window that serves as one page of a tab control.

A tab control draws only the tabs; the page under each tab is a window of your own that you show when its tab is selected. CTabPage is a CWindow that makes such a page: InsertPage adds a tab and creates the page window inside the tab control's display area. Being a CWindow, each page has its own window procedure and everything CWindow offers: AddControl, AnchorControl, SetCtlColors, SetBackColor and the rest work on the page and its controls. The page's controls send their messages to the page's procedure, not to the main window's.

Lifetime. Allocate each page with new. The tab item keeps the object's address, which is how CTabPagePtr finds it again, so the object must live as long as its tab. Deleting the object removes its tab and destroys its window; TabCtl.DestroyAllPages deletes every page of a tab control at once, which is what a main window does in WM_DESTROY.

Showing pages. Pages are created hidden. Show the first one yourself, then in the main window's WM_NOTIFY hide the current page on TCN_SELCHANGING and show the new one on TCN_SELCHANGE. When the tab control changes size, ResizePages fits every page to it again.

Importing

#import "sys/win"
#import "sys/win/gui"
using win, gui

Example

A tab control with two pages, stretched with the window. The first page has an edit box and a button with its own window procedure; the second a list box.

#import "sys/win"
#import "sys/win/gui"
using win, gui

const IDC_TAB    = 1001
const IDC_NAME   = 1002
const IDC_SUBMIT = 1003
const IDC_LIST   = 1004

declare function WndProc( byval hwnd as HWND, byval uMsg as UINT, byval wParam as WPARAM, byval lParam as LPARAM ) as LRESULT
declare function Page1Proc( byval hwnd as HWND, byval uMsg as UINT, byval wParam as WPARAM, byval lParam as LPARAM ) as LRESULT

function main() as long
    SetProcessDpiAwareness( PROCESS_SYSTEM_DPI_AWARE )
    dim pWindow as CWindow = "TabDemo"
    dim hWin as HWND = pWindow.Create( NULL, "CTabPage", @WndProc )
    pWindow.SetClientSize( 420, 260 )
    pWindow.Center()
    dim hTab as HWND = pWindow.AddControl( "Tab", hWin, IDC_TAB, "", 10, 10, 400, 240 )
    pWindow.AnchorControl( hTab, ANCHOR_HEIGHT_WIDTH )

    dim pPage1 as CTabPage ptr = new CTabPage
    dim hPage1 as HWND = pPage1->InsertPage( hTab, 0, "Name", -1, @Page1Proc )
    pPage1->AddControl( "Edit", hPage1, IDC_NAME, "", 15, 20, 250, 24 )
    pPage1->AddControl( "Button", hPage1, IDC_SUBMIT, "&Submit", 280, 19, 90, 26 )
    pPage1->AnchorControl( hPage1, IDC_NAME, ANCHOR_WIDTH )
    pPage1->AnchorControl( hPage1, IDC_SUBMIT, ANCHOR_RIGHT )

    dim pPage2 as CTabPage ptr = new CTabPage
    dim hPage2 as HWND = pPage2->InsertPage( hTab, 1, "List" )
    dim hList as HWND = pPage2->AddControl( "ListBox", hPage2, IDC_LIST, "", 15, 15, 200, 150 )
    pPage2->AnchorControl( hList, ANCHOR_HEIGHT_WIDTH )
    for i as long = 1 to 20
        ListBox.AddString( hList, "Item " & i )
    next

    ShowWindow( hPage1, SW_SHOW )
    return pWindow.DoEvents( SW_NORMAL )
end function

function WndProc( byval hwnd as HWND, byval uMsg as UINT, byval wParam as WPARAM, byval lParam as LPARAM ) as LRESULT
    select case uMsg
        case WM_SIZE
            dim pPage as CTabPage ptr = CTabPagePtr( GetDlgItem( hwnd, IDC_TAB ), -1 )
            if pPage then pPage->ResizePages()
            return 0
        case WM_NOTIFY
            dim pnmh as NMHDR ptr = CBNMHDR( wParam, lParam )
            if pnmh->idFrom = IDC_TAB then
                dim pPage as CTabPage ptr = CTabPagePtr( pnmh->hwndFrom, -1 )
                if pPage then
                    if pnmh->code = TCN_SELCHANGING then ShowWindow( pPage->hTabPage, SW_HIDE )
                    if pnmh->code = TCN_SELCHANGE then ShowWindow( pPage->hTabPage, SW_SHOW )
                end if
            end if
            return 0
        case WM_COMMAND
            if CBCTL( wParam, lParam ) = IDCANCEL then SendMessageW( hwnd, WM_CLOSE, 0, 0 )
            return 0
        case WM_DESTROY
            TabCtl.DestroyAllPages( GetDlgItem( hwnd, IDC_TAB ) )
            PostQuitMessage( 0 )
            return 0
    end select
    return DefWindowProcW( hwnd, uMsg, wParam, lParam )
end function

function Page1Proc( byval hwnd as HWND, byval uMsg as UINT, byval wParam as WPARAM, byval lParam as LPARAM ) as LRESULT
    if uMsg = WM_COMMAND andalso CBCTL( wParam, lParam ) = IDC_SUBMIT andalso CBCTLMSG( wParam, lParam ) = BN_CLICKED then
        SetWindowText( GetAncestor( hwnd, GA_ROOT ), "Hello, " & GetWindowText( GetDlgItem( hwnd, IDC_NAME ) ) )
        return 0
    end if
    return DefWindowProcW( hwnd, uMsg, wParam, lParam )
end function

end main()

Members

CTabPage extends CWindow and has all its members. These are its own:

Member	Does
Destructor	Removes the page's tab and destroys the page window.
InsertPage	Adds a tab and creates the page window for it.
hTabPage	The page window's handle.
ResizePage	Fits the selected tab's page to the tab control.
ResizePages	Fits every page of the tab control to it.

Reference

Destructor

destructor

Finds the object's tab in the tab control, deletes the tab and destroys the page window, then moves the focus to the first tab if any are left. A page that is not in a tab control just has its window destroyed. The CWindow destructor runs after it. The page window's handle and its controls' handles are invalid afterwards.

Example

dim pPage as CTabPage ptr = CTabPagePtr( hCtrl, 1 )
if pPage then delete pPage   ' removes the second tab and its page

Microsoft Learn: TCM_DELETEITEM

InsertPage

function InsertPage( byval hTab as HWND, byval nPage as long, byref wszTitle as wstring = "", byval nImage as long = -1, byval lpfnWndProc as WNDPROC = NULL, byval dwStyle as DWORD = WS_CLIPSIBLINGS or WS_CLIPCHILDREN, byval dwExStyle as DWORD = 0 ) as HWND

Inserts a tab at position nPage and creates the page window with Create as a child of the tab control, covering its display area, hidden. The tab item's lParam holds the object's address, and it is set before the page window is made, so the page's WM_CREATE can already call CTabPagePtr( GetParent( hwnd ), nPage ) to reach the object and add controls. WS_CHILD and WS_EX_CONTROLPARENT are always added to the styles. Each page registers a window class of its own with a generated name.

Parameter	Meaning
hTab	The tab control.
nPage	The zero-based position of the new tab; a position below 0 or past the end puts it last.
wszTitle	The text on the tab, also the page window's title.
nImage	The tab's image in the tab control's image list, or -1 for none.
lpfnWndProc	The page's window procedure. With NULL the page has none of its own and DefWindowProcW handles its messages.
dwStyle	The page window's styles. Add WS_VISIBLE to create it shown.
dwExStyle	The page window's extended styles.

Returns the page window's handle, or NULL when hTab is not a window or the window could not be created.

Example

dim pPage as CTabPage ptr = new CTabPage
dim hPage as HWND = pPage->InsertPage( hCtrl, 0, "General" )
pPage->AddControl( "CheckBox", hPage, 101, "Start with Windows", 15, 15, 200, 22 )

Microsoft Learn: TCM_INSERTITEM

hTabPage

property hTabPage() as HWND

Returns the page window's handle, the one InsertPage returned (the same as hWindow), or NULL before InsertPage.

Example

dim pPage as CTabPage ptr = CTabPagePtr( hCtrl, -1 )
if pPage then ShowWindow( pPage->hTabPage, SW_SHOW )

ResizePage

function ResizePage() as boolean

Fits the page of the tab control's selected tab, whichever page object it is called on, to the tab control's display area.

Returns true; false when the page is not in a tab control.

Example

dim pPage as CTabPage ptr = CTabPagePtr( hCtrl, -1 )
if pPage then pPage->ResizePage()

Microsoft Learn: TCM_ADJUSTRECT

ResizePages

function ResizePages() as boolean

Fits every page of the tab control the page belongs to, shown or hidden, to the tab control's display area. Call it from the main window's WM_SIZE when the tab control is anchored or resized. TabCtl.ResizePages does the same given only the tab control.

Returns true; false when the page is not in a tab control or the tab control has no tabs.

Example

dim pPage as CTabPage ptr = CTabPagePtr( hCtrl, 0 )
if pPage then pPage->ResizePages()

Related functions

Function	Does
CTabPagePtr	Returns the CTabPage of a tab.

CTabPagePtr

function CTabPagePtr( byval hTab as HWND, byval idx as long ) as CTabPage ptr

Reads the object's address from tab idx of a tab control. Pass -1 for the selected tab; the index has no default. The address is the tab item's lParam, so a tab added without InsertPage gives NULL when its lParam is 0, and that value cast to a CTabPage ptr otherwise.

Parameter	Meaning
hTab	The tab control.
idx	The zero-based tab index, or -1 for the selected tab.

Returns the page object, or NULL when there is no such tab, no tab is selected or the tab has no page object.

Example

dim pPage as CTabPage ptr = CTabPagePtr( hCtrl, -1 )
if pPage then SetFocus( GetWindow( pPage->hTabPage, GW_CHILD ) )

Microsoft Learn: TCM_GETITEM

See also

• CWindow, whose members every page has
• TabCtl for the tab control functions, including TabCtl.DestroyPage, TabCtl.DestroyAllPages and TabCtl.ResizePages
• sys/win/gui
• CDialog for tab pages in a dialog