How to indicate that a method was unsuccessful

Question

I have several similar methods, say eg. CalculatePoint(...) and CalculateListOfPoints(...). Occasionally, they may not succeed, and need to indicate this to the caller. For

Answer 1

The model I've used is the same one MS uses with the TryParse methods of various classes.

Your original code:
public Point CalculatePoint(... out Boolean boSuccess);
public List CalculateListOfPoints(... out Boolean boSuccess);

Would turn into public bool CalculatePoint(... out (or ref) Point CalculatedValue);
public bool CalculateListOfPoints(... out (or ref) List CalculatedValues);

Basically you make the success/failure the return value.