Element Operations (Visual Basic)
Element operations return a single, specific element from a sequence.
The standard query operator methods that perform element operations are listed in the following section.
Methods
Method Name | Description | Visual Basic Query Expression Syntax | More Information |
---|---|---|---|
ElementAt | Returns the element at a specified index in a collection. | Not applicable. | Enumerable.ElementAt Queryable.ElementAt |
ElementAtOrDefault | Returns the element at a specified index in a collection or a default value if the index is out of range. | Not applicable. | Enumerable.ElementAtOrDefault Queryable.ElementAtOrDefault |
First | Returns the first element of a collection, or the first element that satisfies a condition. | Not applicable. | Enumerable.First Queryable.First |
FirstOrDefault | Returns the first element of a collection, or the first element that satisfies a condition. Returns a default value if no such element exists. | Not applicable. | Enumerable.FirstOrDefault Queryable.FirstOrDefault Queryable.FirstOrDefault<TSource>(IQueryable<TSource>) |
Last | Returns the last element of a collection, or the last element that satisfies a condition. | Not applicable. | Enumerable.Last Queryable.Last |
LastOrDefault | Returns the last element of a collection, or the last element that satisfies a condition. Returns a default value if no such element exists. | Not applicable. | Enumerable.LastOrDefault Queryable.LastOrDefault |
Single | Returns the only element of a collection, or the only element that satisfies a condition. | Not applicable. | Enumerable.Single Queryable.Single |
SingleOrDefault | Returns the only element of a collection, or the only element that satisfies a condition. Returns a default value if no such element exists or the collection does not contain exactly one element. | Not applicable. | Enumerable.SingleOrDefault Queryable.SingleOrDefault |
See also
Συνεργαστείτε μαζί μας στο GitHub
Μπορείτε να βρείτε την πηγή για αυτό το περιεχόμενο στο GitHub, όπου μπορείτε επίσης να δημιουργήσετε και να εξετάσετε ζητήματα και αιτήματα έλξης. Για περισσότερες πληροφορίες, ανατρέξτε στον οδηγό συνεργατών.