Getting started

TTaskdialog is a dialog box, somewhat like the standard call to Application.MessageBox in the VCL, but much more powerful. The Task Dialog API has been available since Windows Vista and Windows Server 2008, and your application must be theme enabled to use it (go to Project | Options | Application | Runtime Themes | Enable Runtime Themes).

Besides the usual default set of buttons (OK, Cancel, Yes, No, Retry, and Close), you can define extra buttons and many other customizations. The following Windows APIs provides Task Dialog:

 
          
API Name           Description
        
          
TaskDialog           This creates, displays, and operates Task Dialog. The Task Dialog contains application-defined message text and title, icons, and any combination of predefined push buttons. This function does not support the registration of a callback function to receive notifications.
       
          
TaskDialogCallbackProc           This is an application-defined function used with the TaskDialogIndirect function. It receives messages from the Task Dialog when various events occur. TaskDialogCallbackProc is a placeholder for the application-defined function name.
       
          
TaskDialogIndirect           This creates, displays, and operates Task Dialog. The Task Dialog contains application-defined icons, messages, a title, a verification checkbox, command links, push buttons, and radio buttons. This function can register a callback function to receive notification messages.
      
  

More information about API utilization can be obtained from https://msdn.microsoft.com/en-us/library/windows/desktop/bb787471(v=vs.85).aspx.

While the API can be useful in some border cases, the VCL comes with a very nice component that does all the low-level stuff for us. Let's look at an example program and see how simple it is to create a modern application.