Which of these control flows for TryParse is generally advised, if one over the other?

Question

I have a string typeStringwhich I'm trying to parse to an Enum with 30 cases, all of which have rather unique return statements. In some books I have seen a control flow like this used

if (!Enum.TryParse(typeString, true, out replicatingInstrumentType))
{
    Log.Error("Unknown Replicating instrument type: " + typeString);
    return new EmptyInstrument(instrumentIdentifier, Currency.EUR);
}
switch (replicatingInstrumentType)
{
    case TypeA:
    {
        return TypeAReturnStatement;
    }

    // .....
    // more cases here ....
    // .....

    case TypeZ:
    {
        return TypeZReturnStatement;
    }
    default:
    {
        return new EmptyInstrument(instrumentIdentifier, Currency.EUR);
    }
}

whereas I've always figured one should do

if (Enum.TryParse(typeString, true, out replicatingInstrumentType))
{
    switch (replicatingInstrumentType)
    {
        case TypeA:
            {
                return TypeAReturnStatement;
            }

        // .....
        // more cases here ....
        // .....

        case TypeZ:
            {
                return TypeZReturnStatement;
            }
        default:
            {
                return new EmptyInstrument(instrumentIdentifier, Currency.EUR);
            }
    }
}

Log.Error("Unknown Replicating instrument type: " + typeString);
return new EmptyInstrument(instrumentIdentifier, Currency.EUR);

Besides the visual diference, is there any advantage/disadvantage over using one versus the other? Is there a consensus on which approach is better?

Figured that might be the case, voting to close it as opinion-based then, apologies. — HavelTheGreat, Feb 23 '16 at 14:49

Carbine · Accepted Answer · 2016-02-23T14:51:25.513

2

if (!Enum.TryParse(typeString, true, out replicatingInstrumentType))
{
    Log.Error("Unknown Replicating instrument type: " + typeString);
    return new EmptyInstrument(instrumentIdentifier, Currency.EUR);
}

Its called Inverted IF or Replace Nested Conditional with Guard Clauses. Its just for easier readabilty as it reduces the number of nesting and indentation. Lesser the indentation increases your horizontal view area.

edited Feb 23 '16 at 14:51

answered Feb 23 '16 at 14:48

Carbine

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Personally, I hate this....but well, it's an opinion... – Liam Feb 23 '16 at 14:50
1

@Liam I hate when I find conditionals nested 3,4,5 levels deep when a few easy-to-find, easy-to-read guard statements could have just been placed at the top of the method. Likewise, just an opinion. To each their own. Either way, **consistency is the important issue here**. – Dan Bechard Feb 23 '16 at 14:53
There are no winners here... :) – Liam Feb 23 '16 at 15:04

Which of these control flows for TryParse is generally advised, if one over the other?

1 Answers1