
This section provides two examples that use tab controls. The first example demonstrates how to use a tab control to switch between multiple pages of text in an application's main window. The second example demonstrates how to use a tab control to switch between multiple pages of controls in a dialog box.
The example in this section demonstrates how to create a tab control and display it in the client area of the application's main window. The application displays a third window (a static control) in the display area of the tab control. The parent window positions and sizes the tab control and static control when it processes the WM_SIZE message.
There are seven tabs, one for each day of the week. When the user selects a tab, the application displays the name of the corresponding day in the static control. The following global variables are used in this example.
// Global variables
HINSTANCE g_hinst; // handle to application instance
char g_achTemp[256]; // temporary buffer for strings
HWND g_hwndMain; // main application window
HWND g_hwndTab; // tab control
HWND g_hwndDisplay; // handle to static control in
// tab control's display area
The following function creates the tab control and adds a tab for each day of the week. The names of the days are defined as string resources, consecutively numbered starting with IDS_FIRSTDAY (defined in the application's header file). Both the parent window and the tab control must have the WS_CLIPSIBLINGS window style. The application's initialization function calls this function after creating the main window.
// DoCreateTabControl - creates a tab control, sized to fit the
// specified parent window's client area, and adds some tabs.
// Returns the handle to the tab control.
// hwndParent - parent window (the application's main window).
HWND WINAPI DoCreateTabControl(HWND hwndParent)
{
RECT rcClient;
HWND hwndTab;
TCITEM tie;
int i;
// Get the dimensions of the parent window's client area, and
// create a tab control child window of that size.
GetClientRect(hwndParent, &rcClient);
InitCommonControls();
hwndTab = CreateWindow(
WC_TABCONTROL, "",
WS_CHILD | WS_CLIPSIBLINGS | WS_VISIBLE,
0, 0, rcClient.right, rcClient.bottom,
hwndParent, NULL, g_hinst, NULL
);
if (hwndTab == NULL)
return NULL;
// Add tabs for each day of the week.
tie.mask = TCIF_TEXT | TCIF_IMAGE;
tie.iImage = -1;
tie.pszText = g_achTemp;
for (i = 0; i < 7; i++) {
LoadString(g_hinst, IDS_FIRSTDAY + i,
g_achTemp, sizeof(g_achTemp));
if (TabCtrl_InsertItem(hwndTab, i, &tie) == -1) {
DestroyWindow(hwndTab);
return NULL;
}
}
return hwndTab;
}
The following function creates the static control that occupies the tab control's display area. The application's initialization function calls this function after creating the main window and the tab control.
// DoCreateDisplayWindow - creates a child window (a static
// control) to occupy the tab control's display area.
// Returns the handle to the static control.
// hwndParent - parent window (the application's main window).
HWND WINAPI DoCreateDisplayWindow(HWND hwndParent)
{
HWND hwndStatic = CreateWindow("STATIC", "",
WS_CHILD | WS_VISIBLE | WS_BORDER,
0, 0, CW_USEDEFAULT, CW_USEDEFAULT,
hwndParent, NULL, g_hinst, NULL);
return hwndStatic;
}
Following are the relevant portions of the application's window procedure. The application processes the WM_SIZE message to position and size the tab control and the static control. To determine the appropriate position and size for the static control, this example sends the tab control a TCM_ADJUSTRECT message (by using the TabCtrl_AdjustRect macro).
When a tab is selected, the tab control sends a WM_NOTIFY message, specifying the TCN_SELCHANGE notification message. The application processes this notification message by setting the text of the static control.
// MainWindowProc - processes the message for the main window class.
// The return value depends on the message.
// hwnd - handle to the window.
// uMsg - identifier for the message.
// wParam - message-specific parameter.
// lParam - message-specific parameter.
LRESULT CALLBACK MainWindowProc(
HWND hwnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam
)
{
switch (uMsg) {
case WM_SIZE: {
HDWP hdwp;
RECT rc;
// Calculate the display rectangle, assuming the
// tab control is the size of the client area.
SetRect(&rc, 0, 0,
LOWORD(lParam), HIWORD(lParam));
TabCtrl_AdjustRect(g_hwndTab, FALSE, &rc);
// Size the tab control to fit the client area.
hdwp = BeginDeferWindowPos(2);
DeferWindowPos(hdwp, g_hwndTab, NULL, 0, 0,
LOWORD(lParam), HIWORD(lParam),
SWP_NOMOVE | SWP_NOZORDER
);
// Position and size the static control to fit the
// tab control's display area, and make sure the
// static control is in front of the tab control.
DeferWindowPos(hdwp,
g_hwndDisplay, HWND_TOP, rc.left, rc.top,
rc.right - rc.left, rc.bottom - rc.top, 0
);
EndDeferWindowPos(hdwp);
}
break;
case WM_NOTIFY:
switch (HIWORD(wParam)) {
case 0:
.
. // menu command processing
.
case TCN_SELCHANGE: {
int iPage = TabCtrl_GetCurSel(g_hwndTab);
LoadString(g_hinst, IDS_FIRSTDAY + iPage,
g_achTemp, sizeof(g_achTemp));
SendMessage(g_hwndDisplay, WM_SETTEXT, 0
(LPARAM) g_achTemp);
}
break;
}
break;
.
. // additional message processing
.
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
The example in this section demonstrates how to create a dialog box that uses tabs to provide multiple pages of controls. The main dialog box is a modal dialog box. Each page of controls is defined by a dialog box template that has the WS_CHILD style. When a tab is selected, a modeless dialog box is created for the incoming page and the dialog box for the outgoing page is destroyed.
Note In many cases, you can implement multiple-page dialog boxes more easily by using property sheets. For more information about property sheets, see Property Sheets
The template for the main dialog box simply defines two button controls. When processing the WM_INITDIALOG message, the dialog box procedure creates a tab control and loads the dialog template resources for each of the child dialog boxes.
The information is saved in an application-defined structure called DLGHDR. A pointer to this structure is associated with the dialog box window by using the SetWindowLong function. The structure is defined in the application's header file, as follows:
#define C_PAGES 3
typedef struct tag_dlghdr {
HWND hwndTab; // tab control
HWND hwndDisplay; // current child dialog box
RECT rcDisplay; // display rectangle for the tab control
DLGTEMPLATE *apRes[C_PAGES];
} DLGHDR;
The following function processes the WM_INITDIALOG message for the main dialog box. The function allocates the DLGHDR structure, loads the dialog template resources for the child dialog boxes, and creates the tab control.
The size of each child dialog box is specified by the DLGTEMPLATE structure. The function examines the size of each dialog box and uses the macro for the TCM_ADJUSTRECT message to calculate an appropriate size for the tab control. Then it sizes the dialog box and positions the two buttons accordingly. This example sends TCM_ADJUSTRECT by using the TabCtrl_AdjustRect macro.
VOID WINAPI OnTabbedDialogInit(HWND hwndDlg)
{
DLGHDR *pHdr = (DLGHDR *) LocalAlloc(LPTR, sizeof(DLGHDR));
DWORD dwDlgBase = GetDialogBaseUnits();
int cxMargin = LOWORD(dwDlgBase) / 4;
int cyMargin = HIWORD(dwDlgBase) / 8;
TCITEM tie;
RECT rcTab;
HWND hwndButton;
RECT rcButton;
int i;
// Save a pointer to the DLGHDR structure.
SetWindowLong(hwndDlg, GWL_USERDATA, (LONG) pHdr);
// Create the tab control.
InitCommonControls();
pHdr->hwndTab = CreateWindow(
WC_TABCONTROL, "",
WS_CHILD | WS_CLIPSIBLINGS | WS_VISIBLE,
0, 0, 100, 100,
hwndDlg, NULL, g_hinst, NULL
);
if (pHdr->hwndTab == NULL) {
// handle error
}
// Add a tab for each of the three child dialog boxes.
tie.mask = TCIF_TEXT | TCIF_IMAGE;
tie.iImage = -1;
tie.pszText = "First";
TabCtrl_InsertItem(pHdr->hwndTab, 0, &tie);
tie.pszText = "Second";
TabCtrl_InsertItem(pHdr->hwndTab, 1, &tie);
tie.pszText = "Third";
TabCtrl_InsertItem(pHdr->hwndTab, 2, &tie);
// Lock the resources for the three child dialog boxes.
pHdr->apRes[0] = DoLockDlgRes(MAKEINTRESOURCE(DLG_FIRST));
pHdr->apRes[1] = DoLockDlgRes(MAKEINTRESOURCE(DLG_SECOND));
pHdr->apRes[2] = DoLockDlgRes(MAKEINTRESOURCE(DLG_THIRD));
// Determine the bounding rectangle for all child dialog boxes.
SetRectEmpty(&rcTab);
for (i = 0; i < C_PAGES; i++) {
if (pHdr->apRes[i]->cx > rcTab.right)
rcTab.right = pHdr->apRes[i]->cx;
if (pHdr->apRes[i]->cy > rcTab.bottom)
rcTab.bottom = pHdr->apRes[i]->cy;
}
rcTab.right = rcTab.right * LOWORD(dwDlgBase) / 4;
rcTab.bottom = rcTab.bottom * HIWORD(dwDlgBase) / 8;
// Calculate how large to make the tab control, so
// the display area can accommodate all the child dialog boxes.
TabCtrl_AdjustRect(pHdr->hwndTab, TRUE, &rcTab);
OffsetRect(&rcTab, cxMargin - rcTab.left,
cyMargin - rcTab.top);
// Calculate the display rectangle.
CopyRect(&pHdr->rcDisplay, &rcTab);
TabCtrl_AdjustRect(pHdr->hwndTab, FALSE, &pHdr->rcDisplay);
// Set the size and position of the tab control, buttons,
// and dialog box.
SetWindowPos(pHdr->hwndTab, NULL, rcTab.left, rcTab.top,
rcTab.right - rcTab.left, rcTab.bottom - rcTab.top,
SWP_NOZORDER);
// Move the first button below the tab control.
hwndButton = GetDlgItem(hwndDlg, BTN_CLOSE);
SetWindowPos(hwndButton, NULL,
rcTab.left, rcTab.bottom + cyMargin, 0, 0,
SWP_NOSIZE | SWP_NOZORDER);
// Determine the size of the button.
GetWindowRect(hwndButton, &rcButton);
rcButton.right -= rcButton.left;
rcButton.bottom -= rcButton.top;
// Move the second button to the right of the first.
hwndButton = GetDlgItem(hwndDlg, BTN_TEST);
SetWindowPos(hwndButton, NULL,
rcTab.left + rcButton.right + cxMargin,
rcTab.bottom + cyMargin, 0, 0,
SWP_NOSIZE | SWP_NOZORDER);
// Size the dialog box.
SetWindowPos(hwndDlg, NULL, 0, 0,
rcTab.right + cyMargin +
2 * GetSystemMetrics(SM_CXDLGFRAME),
rcTab.bottom + rcButton.bottom + 2 * cyMargin +
2 * GetSystemMetrics(SM_CYDLGFRAME) +
GetSystemMetrics(SM_CYCAPTION),
SWP_NOMOVE | SWP_NOZORDER);
// Simulate selection of the first item.
OnSelChanged(hwndDlg);
}
// DoLockDlgRes - loads and locks a dialog template resource.
// Returns the address of the locked resource.
// lpszResName - name of the resource
DLGTEMPLATE * WINAPI DoLockDlgRes(LPCSTR lpszResName)
{
HRSRC hrsrc = FindResource(NULL, lpszResName, RT_DIALOG);
HGLOBAL hglb = LoadResource(g_hinst, hrsrc);
return (DLGTEMPLATE *) LockResource(hglb);
}
The following function processes the TCN_SELCHANGE notification message for the main dialog box. The function destroys the dialog box for the outgoing page, if any. Then it uses the CreateDialogIndirect function to create a modeless dialog box for the incoming page.
// OnSelChanged - processes the TCN_SELCHANGE notification.
// hwndDlg - handle to the parent dialog box.
VOID WINAPI OnSelChanged(HWND hwndDlg)
{
DLGHDR *pHdr = (DLGHDR *) GetWindowLong(
hwndDlg, GWL_USERDATA);
int iSel = TabCtrl_GetCurSel(pHdr->hwndTab);
// Destroy the current child dialog box, if any.
if (pHdr->hwndDisplay != NULL)
DestroyWindow(pHdr->hwndDisplay);
// Create the new child dialog box.
pHdr->hwndDisplay = CreateDialogIndirect(g_hinst,
pHdr->apRes[iSel], hwndDlg, ChildDialogProc);
}
The following function processes the WM_INITDIALOG message for each of the child dialog boxes. You cannot specify the position of a dialog box created using the CreateDialogIndirect function. This function uses the SetWindowPos function to position the child dialog within the tab control's display area.
// OnChildDialogInit - Positions the child dialog box to fall
// within the display area of the tab control.
VOID WINAPI OnChildDialogInit(HWND hwndDlg)
{
HWND hwndParent = GetParent(hwndDlg);
DLGHDR *pHdr = (DLGHDR *) GetWindowLong(
hwndParent, GWL_USERDATA);
SetWindowPos(hwndDlg, HWND_TOP,
pHdr->rcDisplay.left, pHdr->rcDisplay.top,
0, 0, SWP_NOSIZE);
}
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