In the last installment, we’ve seen using the basic version of task dialog. But usually when we see the task dialogs in Windows Vista or 7, it’s more detailed and can have flashy icons etc. Let’s see how to take more control over the task dialogs.
TaskDialogIndirect function can be used to have more options with task dialogs. TASKDIALOGCONFIG structure is used along with TaskDialogIndirect API.
As you’re seeing above the task dialog contains different type of controls, icons and capable of displaying more information to the user. It can have lengthy big buttons, radio buttons, checkbox, footer area, progressbar, custom icon, displaying predefined buttons like OK, Cancel, Yes, No etc. even we can have control over the buttons in the titlebar( minimize, maximize button etc)
The following code describes creating a task dialog with more flexible options. User can specify the callback functions which can be used to control the behavior if the controls and contents in the task bar. Filling the TASKDIALOGCONFIG structure is simple and straight forward as we’re seeing the code. The detailed option can be obtained from MSDN page.
HRESULT CALLBACK CTaskDialogSampleDlg::TaskDialogCallbackProc(
__in HWND hwnd,
__in UINT uNotification,
__in WPARAM wParam,
__in LPARAM lParam,
__in LONG_PTR dwRefData
)
{
if( TDN_CREATED == uNotification )
{
::SendMessage( hwnd, TDM_SET_BUTTON_ELEVATION_REQUIRED_STATE, IDOK, TRUE );
::SendMessage( hwnd, TDM_SET_PROGRESS_BAR_RANGE, 0, 100 );
}
else if( TDN_HYPERLINK_CLICKED == uNotification )
{
ShellExecute( 0, L"open", (LPCTSTR) lParam, 0, 0, SW_SHOW );
}
else if( TDN_TIMER == uNotification )
{
static int i = 0;
::SendMessage( hwnd, TDM_SET_PROGRESS_BAR_POS, i++,0 );
}
return 0;
}
void CTaskDialogSampleDlg::OnBnClickedButton1()
{
int nButtonPressed = 0;
TASKDIALOGCONFIG config = {0};
const TASKDIALOG_BUTTON buttons[] = {
{ IDOK, L"Elevate Privilege" },
{ IDCANCEL, L"Run with user privilege" }
};
const TASKDIALOG_BUTTON radiobuttons[] = {
{ IDCANCEL, L"Test Radio" }};
config.cbSize = sizeof(config);
config.hInstance = AfxGetApp()->m_hInstance;
config.dwCommonButtons = TDCBF_OK_BUTTON | TDCBF_CANCEL_BUTTON;
config.pszMainIcon = TD_SHIELD_ICON;
config.pszMainInstruction = L"Main Instruction";
config.pszContent = L"This is the content.";
config.pszVerificationText = L"Conifirm license agreement";
config.pButtons = buttons;
config.cButtons = ARRAYSIZE(buttons);
config.pRadioButtons = radiobuttons;
config.cRadioButtons = ARRAYSIZE( radiobuttons );
config.dwFlags = TDF_SHOW_PROGRESS_BAR |
TDF_EXPAND_FOOTER_AREA | TDF_ENABLE_HYPERLINKS | TDF_CAN_BE_MINIMIZED
| TDF_USE_COMMAND_LINKS | TDF_CALLBACK_TIMER;
config.pszExpandedInformation = _T( "<a href=\"http://codereflect.com/\" >Codereflect.com</a>" );
config.pfCallback = TaskDialogCallbackProc;
BOOL bVerification = FALSE;
TaskDialogIndirect(&config, &nButtonPressed, NULL, &bVerification);
switch (nButtonPressed)
{
case IDOK:
break; // the user pressed button 0 (change password).
case IDCANCEL:
break; // user canceled the dialog
default:
break; // should never happen
}
}
The callback function is also easy to manage. There are predefined set of events for each type of control and we can simply make use of these controls by sending various messages to update its state and values. One of the best example is updating the progressbar during the lifetime of messagebox. Once the timer is enabled, the callback function will be automatically fired on discrete time interval. The notify messages are specified in detail in MSDN Documentation. Please check it.
To compile this source code, please use latest version of Visual Studio 2010 or any prior version with Windows Vista/7 SDK. You can also use express edition of Visual C++ to try this API.
