linq Getting started with linq Query Syntax and Method Syntax

Example

Query syntax and method syntax are semantically identical, but many people find query syntax simpler and easier to read. Let’s say we need to retrieve all even items ordered in ascending order from a collection of numbers.

C#:

int[] numbers = { 0, 1, 2, 3, 4, 5, 6 };

// Query syntax:
IEnumerable<int> numQuery1 =
            from num in numbers
            where num % 2 == 0
            orderby num
            select num;

// Method syntax:
IEnumerable<int> numQuery2 = numbers.Where(num => num % 2 == 0).OrderBy(n => n);

VB.NET:

Dim numbers() As Integer = { 0, 1, 2, 3, 4, 5, 6 }

' Query syntax: '
Dim numQuery1 = From num In numbers
                 Where num Mod 2 = 0
                 Select num
                 Order By num

' Method syntax: '
Dim numQuery2 = numbers.where(Function(num) num Mod 2 = 0).OrderBy(Function(num) num)

Remember that some queries must be expressed as method calls. For example, you must use a method call to express a query that retrieves the number of elements that match a specified condition. You also must use a method call for a query that retrieves the element that has the maximum value in a source sequence. So that might be an advantage of using method syntax to make the code more consistent. However, of course you can always apply the method after a query syntax call:

C#:

int maxNum =
    (from num in numbers
     where num % 2 == 0
     select num).Max();

VB.NET:

Dim maxNum =
    (From num In numbers
     Where num Mod 2 = 0
     Select num).Max();