FirstOrDefault returns NullReferenceException if no match is found

Question

Here is my code:

string displayName = Dictionary.FirstOrDefault(x => x.Value.ID == long.Parse(options.ID)).Value.DisplayName;

The code works

Answer 1

You can use a combination of other LINQ methods to handle not matching condition:

var res = dictionary.Where(x => x.Value.ID == someID)
                    .Select(x => x.Value.DisplayName)
                    .DefaultIfEmpty("Unknown")
                    .First();