How to find an element in c# Generic List

The following sample code demonstrates you how to find a matching element in the object list.

Let's say we have an object called Person with public properties PersonID, Name, Age, Gender as defined below.

using System.Collections.Generic.List;

public class Person
{
public int PersonID {get; set;}
public string Name {get; set;}
public int Age {get; set;}
public bool Gender {get; set;}
}

class program
{
public static void Main(string[] args)
{
// Let's say we have a method defined as dbAccess.GetPersons() to
//return all the records from Person table and populates the
//list object "persons" as shown below.
List persons = dbAccess.GetPersons();

int personIDToFind = 1234;
//Find person in persons list by PersonID using predicate
//"p=>p.PersonID == personIDToFind"
Person personByFindOperation = persons.Find( p=>p.PersonID == personIDToFind );

string personName = "Kiran"
//Find person in persons list by Name using predicate
//"p=>p.Name == personName"
Person personByFindOperation2 = persons.Find( p=>p.Name == personName );

}
}

Note: The Find method of List returns the first occurrence of the exact match within the entire System.Collections.Generic.List.

How to sort list of objects in C#

The following code helps in sorting list of objects based on some property’s value.

public class Person
{
public int age;
public string name;

public Person(int age, string name)
{
this.age = age;
this.name = name;
}
}

List people = new List();

people.Add(new Person(50, “Kiran”));
people.Add(new Person(30, “Raghava”));
people.Add(new Person(26, “Andrew”));
people.Add(new Person(24, “Praveen”));
people.Add(new Person(5, “Sudhir”));
people.Add(new Person(6, “Prudhvi”));

Console.WriteLine(”Unsorted list”);
people.ForEach(delegate(Person p) { Console.WriteLine(String.Format(”{0} {1}”, p.age, p.name)); });

Console.WriteLine(”Sorted list, by name”);
people.Sort(delegate(Person p1, Person p2) { return p1.name.CompareTo(p2.name); });
people.ForEach(delegate(Person p) { Console.WriteLine(String.Format(”{0} {1}”, p.age, p.name)); });

people.Sort(delegate(Person p1, Person p2) { return p1.age.CompareTo(p2.age); });
Console.WriteLine(”Sorted list, by age”);
people.ForEach(delegate(Person p) { Console.WriteLine(String.Format(”{0} {1}”, p.age, p.name)); });