Question

I have a number of methods where I perform validation – tryParse being one of the main functions i use.

I end up with code like this:

bool isValid = true;

int dealId;
isValid = !int.TryParse(strArr[0], out dealId) ? false : isValid;

DateTime createdOn;
isValid = !DateTime.TryParse(strArr[1], out createdOn) ? false : isValid;

isValid = !tmp.Add(new BookmarkedDeal(userId, dealId, createdOn)) ? false : isValid;

Is there a better way of setting isValid to false only if the result is false?

Answer 1

This depends on what you definition of “better” is, but you can do something like this:

int dealId;
DateTime createdOn;

return int.TryParse(strArr[0], out dealId) &&
       DateTime.TryParse(strArr[1], out createdOn) && 
       tmp.Add(new BookmarkedDeal(userId, dealId, createdOn))

(assuming of course you are returning this from a method, otherwise, you can just set the value of this to a bool isValid and use it as you did before)

&& is called the conditional-AND operator. The basic idea is it will only evaluate far enough to see if the returned value will satisfy the condition(s). So first it will check to see if int.TryParse() returns a true, if it does, it will check DateTime.TryParse() and then the following method if it returns true. The beauty of this operator is if any fails, then it knows that it cannot possibly be true and returns a false immediately.

(There is also a conditional-OR operator (||) that acts the same way, but if evaluates only fair enough until it hits a true, hence making the entire expression true).