Is there a better way to check if an entire string was matched?

Question

I'm parsing a text file line by line and for each line I have a special regex. However in one case a pattern is matching two lines. One that is a correct match and another line only partialy because a couple of values are optional.

Invalid match:

BNE1010/1000 HKG1955/2005 7/PLD/CLD/YLD

matches patial string (shouln't match this at all):

BNE1010/1000

Correct match (matches the entire string):

RG878A/21AUG15 GIG/BOG 1/RG/AV 3/AV 4/AV 5/RG 6/AV081C/22 7/CDC/YD 9/TP

The regex for this is quite long and contains several optionl groups:

^(?<FlightDesignator>([A-Z0-9]{2}[A-Z]?)([0-9]{3,4}))(?<OperationalSuffix>[A-Z])?(?<FlightIdentifierDate>\/(\d{2})([A-Z]{3})?(\d{2})?)?(\s(?<FlightLegsChangeIdentifier>(\/?[A-Z]{3})+)(?=(\s|$)))?(\s1(?<JointOperationAirlineDesignators>(\/.{2}[A-Z]?)+))?(\s3\/(?<AircraftOwner>([A-Z]{2}|.)))?(\s4\/(?<CockpitCrewEmployer>(.+?)(?=(?: \d\/|$))))?(\s5\/(?<CabinCrewEmployer>([A-Z]{2}|.)))?(?<OnwardFlight>\s6\/(([A-Z0-9]{2}[A-Z]?)([0-9]{3,4}))([A-Z])?(\/(\d{2})([A-Z]{3})?(\d{2})?)?)?(\s7\/(?<MealServiceNote>(\/?[A-Z]{0,3})+))?(\s9\/(?<OperatingAirlineDisclosure>(.{2}[A-Z]?)))?

I think there is no need to study the entire regex becasue it's build dynamically from smaller patterns at runtime and all the parts work correctly. Also lots of combinations are tested with unit tests and they all work... as long as I try to parse ony the line that should be matched by the pattern.

Currently I'm checking if the entire string is matched by

match.Group[0].Value == line

but I find it's quite ugly. I know from JavaScript the regex engine provides an Index property where the regex engine stopped. So my idea was to compare the index with the length of the string. Unfortunatelly I wasn't able to find such a property in C#.

Another idea would be to modify the regex so that it matches only one line and no partial lines.

Example: https://regex101.com/r/dM5wU4/1

The example contains only two cases because there aren't actually any combinations that would change its behavior. I could remove some parameters but it wouldn't change anything.

EDIT:

I've edited my question. Sorry to every for not providing all the information at the first time. I won't ask any more questions when writing on the phone :) It wasn't a good idea. Hopefully it won't get closed now.

You asked whether I could simplify the regex. I would do it if I could and knew how. If it was easy I wouldn't have asked. The problem started as the regex ans string became bigger during development. Now they are at the production length and I can't actually make them shorter even for the sake of the quesion, sorry.

EDIT-2:

I found the reason why I couldn't find the inherited Index and Length properties of the Match class.

For some strange reason when selecting the Match class and pressing F1 Visual Studio opened the wrong help page (Match Properties) even though I'm not working with the Micro Framework. I didn't notice that but I was indeed wondering why there is very little information. Thx to @Jamiec for the correct link. I won't trust Visual Studio anymore when hitting F1.

Answer 1

_{Disclaimer: Im going to add this, but I doubt its the solution. If it's not this part will get deleted in short order}

You can add a $ at the end of your regular expression. This stops your first example matching but continues to match the second example.

As you've not provided any more than 2 examples, its unclear if this actually solves all your cases or just that one specific false positive.

---

My question is whether it is possible to check if a regular expression matched the entire sting without checking the first group against the original line?

If you're not adverse to checking the entire match to the length of the string you can do that too:

var regex = new Regex(@"^(?<FlightDesignator>([A-Z0-9]{2}[A-Z]?)([0-9]{3,4}))(?<OperationalSuffix>[A-Z])?(?<FlightIdentifierDate>\/(\d{2})([A-Z]{3})?(\d{2})?)?(\s(?<FlightLegsChangeIdentifier>(\/?[A-Z]{3})+)(?=(\s|$)))?(\s1(?<JointOperationAirlineDesignators>(\/.{2}[A-Z]?)+))?(\s3\/(?<AircraftOwner>([A-Z]{2}|.)))?(\s4\/(?<CockpitCrewEmployer>(.+?)(?=(?: \d\/|$))))?(\s5\/(?<CabinCrewEmployer>([A-Z]{2}|.)))?(?<OnwardFlight>\s6\/(([A-Z0-9]{2}[A-Z]?)([0-9]{3,4}))([A-Z])?(\/(\d{2})([A-Z]{3})?(\d{2})?)?)?(\s7\/(?<MealServiceNote>(\/?[A-Z]{0,3})+))?(\s9\/(?<OperatingAirlineDisclosure>(.{2}[A-Z]?)))?");

var input1 = @"BNE1010/1000 HKG1955/2005 7/PLD/CLD/YLD";
var input2 = @"RG878A/21AUG15 GIG/BOG 1/RG/AV 3/AV 4/AV 5/RG 6/AV081C/22 7/CDC/YD 9/TP";

var match1 = regex.Match(input1);
var match2 = regex.Match(input2); 

Console.WriteLine(match1.Length == input1.Length); // False
Console.WriteLine(match2.Length == input2.Length); // True

Live example: http://rextester.com/NIBE6349