C#: How to convert a list of objects to a list of a single property of that object?
C#LinqListC# Problem Overview
Say I have:
IList<Person> people = new List<Person>();
And the person object has properties like FirstName, LastName, and Gender.
How can I convert this to a list of properties of the Person object. For example, to a list of first names.
IList<string> firstNames = ???
C# Solutions
Solution 1 - C#
List<string> firstNames = people.Select(person => person.FirstName).ToList();
And with sorting
List<string> orderedNames = people.Select(person => person.FirstName).OrderBy(name => name).ToList();
Solution 2 - C#
IList<string> firstNames = (from person in people select person.FirstName).ToList();
Or
IList<string> firstNames = people.Select(person => person.FirstName).ToList();
Solution 3 - C#
firstNames = (from p in people select p=>p.firstName).ToList();
Solution 4 - C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace TestProject
{
public partial class WebForm3 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
SampleDataContext context = new SampleDataContext();
List<Employee> l = new List<Employee>();
var qry = from a in context.tbl_employees where a.Gender=="Female"
orderby a.Salary ascending
select new Employee() {
ID=a.Id,
Fname=a.FName,
Lname=a.Lname,
Gender=a.Gender,
Salary=a.Salary,
DepartmentId=a.DeparmentId
};
l= qry.ToList();
var e1 = from emp in context.tbl_employees
where emp.Gender == "Male"
orderby emp.Salary descending
select emp;
GridView1.DataSource = l;
GridView1.DataBind();
}
}
public class Employee
{
public Int64 ID { get; set; }
public String Fname { get; set; }
public String Lname { get; set; }
public String Gender { get; set; }
public decimal? Salary { get; set; }
public int? DepartmentId { get; set; }
}
}
Solution 5 - C#
using System.Collections.Generic;
using System.Linq;
IList<Person> people = new List<Person>();
IList<string> firstNames = people.Select(person => person.FirstName).ToList();
Solution 6 - C#
This will turn it to a list:
List<string> firstNames = people.Select(person => person.FirstName).ToList();
This will return one (the first one):
var firstname = people.select(e => e.firstname).FirstOrDefault();