While working with data it’s not always required that we fetch all
the records. Many a times we only need to fetch
the first record, or some records in some index, in
the record set. With LINQ we can get
the desired record very easily with
the help of
the provided element operators.
Simple get
the first record.
If you want only
the first record in record set we can use
the first method [Note that this can also be done easily done with
the help of
the take method by providing
the value as one].
List<Product> products = GetProductList();
Product product12 = (
from prod in products
where prod.ProductID == 12
select prod)
.First();
We can also very easily put some condition on which
first record to be fetched.
string[] strings = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
string startsWithO = strings.First(s => s[0] == 'o');
In
the above example
the result would be “one” because that is
the first record starting with “o”.
Also
the fact that there will be chances that there are no value returned in
the result set. When we know such possibilities we can use
the FirstorDefault() method to return
the first record or incase there are no records get
the default value.
int[] numbers = {};
int firstNumOrDefault = numbers.FirstOrDefault();
In case we do not want
the first record but
the second or
the third or any other later record then we can use
the ElementAt() method. In
the ElementAt() method we need to pass
the index number for which we want
the record and we will receive
the result for that element.
int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
int fourthLowNum = (
from num in numbers
where num > 5
select num )
.ElementAt(1);
Vikram
