Hmm. 'Sort of' works:

   class Program
    {
        static void Main(string[] args)
        {
            Test t = new Test();
          
            for (int x =0 ;x < 10 ;x++)
            {
                if (x%3 == 0)
                {
                    t.C++;
                }  //Breakpoint here on condition  t.C has changed
            }

        }
    }

    public class Test
    {
        public int C { get; set; }
    }

But that's not really the same as setting a global breakpoint when t.C changes - I'm checking at a specific location.....

>Nope. I've done it.
>
>Set a break point
>Right-Click on the red dot in the gutter.
>Select Condition
>
>>Don't think so. You can set a condition or a filter or monitor the hit count - but not break automatically on a change (unless in the Setter of a property :-})
>>
>>UPDATE: Unless it's C++ .....