I often encounter this problem – I need to get some value, if it exists, and then do something with that value.

Getting that value becomes a separate method, and since that value might not exist, I need to indicate that somehow. For example, I might have a method that returns a productId if a product is attached to the form the user is filling out. If it doesn’t exist, I can return 0, which is an invalid productId, which is a magic number.

My current problem with this instance is this:

public int GetProductIdFromFormIfAny(JObject form) {   int productId = 0; //default to 0    IList<FormComponentMetadata> formFields = ParseFormForDropdowns(form);   bool isProductAttached = formFields.Any(field => field.DataLookupTable == "Products");   if(isProductAttached){     FormComponentMetadata productField = formFields       .Single(field => field.DataLookupTable == "Products");     string filterStringContainingProductId = productField.DataLookupFilter;     productId = filterStringContainingProductId.Split("=")[1];   }   return productId; } 

I don’t know how to get around the magic number issue. I can create a new class, which holds an id and a bool indication whether or not that id exists, but that seems very heavy-handed and a LOT of extra code that someone has to maintain, even though the tradeoff is clarity.

As a side note, this is what comes back for the filterStringContainingProductId: "data_lookup_filter":"Product_ID=9" – I am not sure how to make the Split("=")[1] clear without comments or constants, which, again, seem heavy.