LINQ Method Syntax

LINQ (Language Integrated Query) provides two ways to write queries in C#

1. Query Syntax (Query Expression Syntax)
2. Method Syntax (Fluent Syntax)

Method Syntax

LINQ Method Syntax, also called Fluent Syntax, uses extension methods such as Where(), Select(), OrderBy() and others, defined in the System.Linq namespace. It provides the same functionality as Query Syntax but often offers more flexibility, especially for complex queries.

Instead of SQL-like keywords, Method Syntax uses lambda expressions as parameters to LINQ methods.

Creating LINQ Query using Method Syntax

Step 1: First add System.Linq namespace in your code.

using System.Linq;

Step 2: Next, create a data source on which you want to perform operations.

For example:

List<string> my_list = new List<string>() {

"This is my Dog",

"Name of my Dog is Robin",

"This is my Cat",

"Name of the cat is Mewmew"

};

Step 3: Create the query using LINQ methods like Where(), Select(), etc.

For example:

var res = my_list.Where(l => l.Contains("my")).Select(l => l);

Here:

• Where(l => l.Contains("my")) applies the filter.
• Select(l => l) projects the result (in this case, returns the same element).
• l is the range variable, representing each element in the collection.

Step 4: Execute the query by using a foreach loop.

For example:

foreach (var q in res) {
Console.WriteLine(q);
}

Example: Program to demonstrate LINQ Method Syntax

using System;
using System.Linq;
using System.Collections.Generic;

class GFG {

    static public void Main() {

        // Data source
        List<string> my_list = new List<string>() {
            "This is my Dog",
            "Name of my Dog is Robin",
            "This is my Cat",
            "Name of the cat is Mewmew"
        };
        // Creating LINQ Query using Method Syntax
        var res = my_list.Where(l => l.Contains("my")).Select(l => l);

        // Executing LINQ Query
        foreach (var q in res) {Console.WriteLine(q);
        }
    }
}

This is my Dog
Name of my Dog is Robin
This is my Cat

Related Articles

• LINQ (Language Integrated Query)
• Query Syntax (Query Expression Syntax)

Suggested Quiz

Edit Quiz

3 Questions

In method syntax, which LINQ method is used for filtering elements based on a condition?

• A

  Select

• B

  GroupBy

• C

  Where

• D

  Take

Explanation:

The Where() method is used with lambda expressions to filter elements that satisfy a condition.

In LINQ Method Syntax, which of the following is used to filter data?

• A

  Select()

• B

  Where()

• C

  OrderBy()

• D

  GroupBy()

Explanation:

What is the purpose of the lambda expression l => l.Contains("my") in the following query?

C#

var res = my_list.Where(l => l.Contains("my")).Select(l => l);

• A

  Projects the result

• B

  Filters elements based on a condition

• C

  Sorts the elements

• D

  Executes the query

Explanation:

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