Every programmer must be familiar with the MessageBox es in any platform. It’s the simplest way to notify the user to take an action or provide notifications. Windows provides standard message box functionality with MessageBox API for displaying MessageBox with most frequently used buttons (OK, Cancel, Yes, No etc) and icons (error, warning, info etc.) This is again limited in programmer’s point of view and most we used to create our own messagebox to meet our extended purpose.

Windows UI has revamped since windows Vista and the UI experience was totally new from its predecessors. Most of the Windows Vista/7 applications display and extended form of messagebox called task dialog. Task dialog gives us more flexibility over the typical messagebox we used to have in Windows. We can display progress bars, extended information on footer, custom icons, predefined icons like Shield Icons (to indicate UAC elevation is required for operation etc.)

Task dialog comes with a simple set of interfaces and also provides an advanced version of interface to take control over what all we’re displaying in the task dialog

Displaying a Simple Taskbar

A simple task dialog can be displayed by calling TaskDialog API. The default buttons like OK, Yes, No, Cancel, Retry and close button. It’s simple as displaying a normal messagebox. The major difference is that we can have a custom icon, also a main instruction to show the intention of task dialog and main content provides further description of it. Organization of message is better readable and can have more focus than standard messagebox.

	TASKDIALOG_COMMON_BUTTON_FLAGS tButton =
		TDCBF_OK_BUTTON| TDCBF_YES_BUTTON|
		TDCBF_NO_BUTTON| TDCBF_CANCEL_BUTTON|
		TDCBF_RETRY_BUTTON| TDCBF_CLOSE_BUTTON;

	int nClickedBUtton;
	TaskDialog( m_hWnd, NULL,
		_T("Demonstrating TaskDialog API"),
		_T("This is the main instruction"), _T("This shows the main content"),
		tButton,
		MAKEINTRESOURCE( IDI_SHIELD ),
		&nClickedBUtton );

In the above code you can see the default buttons are displayed with binary OR “|” operator. The return value is passed as parameter and can refer after calling the API. The return value of the function gives the error status. S_OK means the dialog was successfully displayed. the details of the parameters and return values are described in the TaskDialog API documentation. In the next installment, let’s have a look at advanced usage of Task Dialog.