TechTalk: LINQ and Lambda expression

Hi All,

This is a simple application showing how to use LINQ and Lambda expression

Step 1:

Create a simple Customer Class:

public class Customer

{

public int Id;public string Name;public string City;

public Customer(int id, string name, string city)

{

Id = id;Name = name;City = city;

}

Step 2:

Add few customers to the class as below:

List<Customer> customers = new List<Customer>();

customers.Add(new Customer(1, "Dave", "Sarasota"));

customers.Add(new Customer(2, "John", "Tampa"));

customers.Add(new Customer(3, "Abe", "Miami"));

Next we try to write some test method which gets required customer on some condition.

Let’s name it as getCust

Sorry I am not following any naming conventions here J ……

The method looks as below:

This method tries to fetch the result from the list using the below:

· FirstOtDefault

· FindAll

· Find

· Where

· select

public static Customer getCust(List<Customer> lcust)

{

Customer objcust = null;

//using simple FirstOtDefault

objcust = lcust.FirstOrDefault(c => c.Id == 1);

//Using FindAll

objcust = lcust.FindAll(c => c.Id == 1).FirstOrDefault();

//using Predicate and using Find

Predicate<Customer> pred = item => item.Id == 2;

objcust = lcust.Find(pred);

//using Func for Where

Func<Customer, bool> whereFunc = delegate(Customer cutitemem)

{

return cutitemem.Id == 3;

};

objcust = lcust.Where(whereFunc).FirstOrDefault();

//Using simple LINQ

var result = from c in lcust

where c.Id.Equals(1)

select c;

objcust = result.ToList<Customer>().FirstOrDefault();

return objcust;

}

As you can see the above method shows different techniques of using LINQ and Lambda.

ok.. here is the full code :)

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace SimpleLINQ_Lamda

{

class Program

{

static void Main(string[] args)

{