What is the use of first or default in C#?
Use the FirstorDefault() method to return the first element of a sequence or a default value if element isn’t there. List val = new List { }; Now, we cannot display the first element, since it is an empty collection. For that, use the FirstorDefault() method to display the default value.
What is the difference between first and first or default?
The major difference between First and FirstOrDefault is that First() will throw an exception if there is no result data for the supplied criteria whereas FirstOrDefault() will return the default value (null) if there is no result data. First() will throw an exception if there is no result data, as you can see below.
Should I use FirstOrDefault first?
Use First() when you are sure that a query must return a record, and use FirstOrDefault() when you are not sure whether it will return a record or not.
What is first or default in MVC?
Element Operators: First & FirstOrDefault Returns the first element of a collection, or the first element that satisfies a condition. FirstOrDefault. Returns the first element of a collection, or the first element that satisfies a condition.
Is FirstOrDefault faster than first?
FirstOrDefault is signicantly faster than SingleOrDefault while viewing ANTS profiler.
What is difference between FirstOrDefault and SingleOrDefault?
SingleOrDefault() – Same as Single(), but it can handle the null value. First() – There is at least one result, an exception is thrown if no result is returned. FirstOrDefault() – Same as First(), but not thrown any exception or return null when there is no result.
What is IEnumerable and IQueryable in C#?
The main difference between IEnumerable and IQueryable in C# is that IQueryable queries out-of-memory data stores, while IEnumerable queries in-memory data. Moreover, IQueryable is part of . NET’s System. LINQ namespace, while IEnumerable is in System. Collections namespace.
What is difference between single default and FirstOrDefault in Linq?
Which is faster SingleOrDefault or FirstOrDefault?
FirstOrDefault usually perform faster as compared SingleOrDefault, since these iterate the collection until they find the first match. While SingleOrDefault iterate the whole collection to find one single match.
What is difference between SingleOrDefault and FirstOrDefault?
Is FirstOrDefault slow?
We use Redgate’s Performance profiler to find some performance leaks. Our tool uses Linq to objects in several methods. But we have noticed that a FirstOrDefault takes very long on collections with +/- 1000 objects. The profiler also alerts that the query is very slow.