How to implement IN clause in LINQ/LAMBDA Query expression?Explain with an example.

Answer:

This can be done using the "Contains" extension method. Example follows.

Suppose we have a person class as under

public class Person

{

	public string  PersonName { get; set; }

	public string JobTitle { get; set; }



	public override string ToString()

	{

		return "Person Name: " + PersonName + " JobTitle:" + JobTitle;

	}

}

Then populate the Person collection as under

private static List<Person> PreparePersonCollection()

{

	List<Person> lstPersonCollection = new List<Person>();

	lstPersonCollection.Add(new Person { PersonName = "Amitav Sen", JobTitle = "Design Engineer" });

	lstPersonCollection.Add(new Person { PersonName = "Bhavini Dey", JobTitle = "Software Engineer" });

	lstPersonCollection.Add(new Person { PersonName = "Debasis Basu", JobTitle = "Software Engineer" });

	lstPersonCollection.Add(new Person { PersonName = "Kartik Moin", JobTitle = "Lead Engineer" });

	lstPersonCollection.Add(new Person { PersonName = "Shahjahan Khan", JobTitle = "Technical Lead" });



	return lstPersonCollection;

}

Suppose we want to get the list of Person who has job Title as "Design Engineer", "Software Engineer".

The complete query will be as under

List<Person> source = PreparePersonCollection();



string[] strJobTitleToInclude = new string[] { "Design Engineer", "Software Engineer" };



source

	.Where(i=>strJobTitleToInclude.Contains(i.JobTitle))

	.ToList()

	.ForEach(i => Console.WriteLine(i.ToString()));

Output

Person Name: Amitav Sen JobTitle:Design Engineer

Person Name: Bhavini Dey JobTitle:Software Engineer

Person Name: Debasis Basu JobTitle:Software Engineer