How do i check if a button is clicked?

Adding continously - but how?

Are you using a loop in the same thread? If yes, you cannot handle the Stop event that easily. The event would not be raised, since message-pump will not get time to process the user's action. You either need to call PeekMessage within the loop, or make your program multithreaded.


Read this article:
The Practical Guide to Multithreading - Part 1[^]

put a call procedure into the loop that looks to the button, and if pressed breaks.

First add one Button in your Dialog/View. Then set a name of that Button ( e.g. I set a name BTN_STOP_NOW). Now double click on that button it will add one Method autometically

OnBTN_STOP_NOW()
{

//Add your code to stop adding Item into the list
//NOTE: You need not to check for any If condition.
//Anything you put ib this method, that will take care
//by windows autometically when this button will b pressed
}

When we add any controls, that will gets added inside windows DDX/PDX Map. Which will used by windows at run time, to get validated of that controls & for messages passing purpose. So, window will take care of that autometically, to check if the button pressed or not

I've offer a simple way: create a boolean variables and then check state of variable when a button is clicked.