Use .DefaultIfEmpty() instead of .FirstOrDefault() ?? String.Empty;

Question

How can I integrate the .DefaultIfEmpty() extension method so I have not to use

.FirstOrDefault() ?? String.Empty;

Code:

(from role in roleList
let roleArray = role.RoleId.Split(new char[] { WorkflowConstants.WorkflowRoleDelimiter })
where roleArray.Length.Equals(_SplittedRoleIdArrayLength) && 
      HasAccessToCurrentUnit(roleArray[_UnitIndexInRoleId])
select roleArray[_LevelIndexInRoleId]).FirstOrDefault() ?? String.Empty;

Answer 1

You could use:

var query = ...;

return query.DefaultIfEmpty(string.Empty).First();

But this doesn't reduce the complexity IMO.

Answer 2

If you're interested in extension method then you could use something like this:

public static class Helpers
{
    public static string FirstOrEmpty(this IEnumerable<string> source)
    {
        return source.FirstOrDefault() ?? string.Empty;
    }
}

Edit

This method isn't generic because then we'd have to use default(T) and it'll give us null instead of string.Empty.