Implementing Paging in a Generic List using LINQ

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It's quite common of users to bind their Generic List to an ASP.NET control. However if the list is huge, you may need to implement Paging functionality. Here's a simple way to do implement Paging functionality using LINQ

C#

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

 

public partial class LINQ : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        List<Employee> empList = new List<Employee>();

        empList.Add(new Employee() { ID = 1, FName = "John",  DOB = DateTime.Parse("12/11/1971")});

        empList.Add(new Employee() { ID = 2, FName = "Mary",  DOB = DateTime.Parse("01/17/1961")});

        empList.Add(new Employee() { ID = 3, FName = "Amber", DOB = DateTime.Parse("12/23/1971")});

        empList.Add(new Employee() { ID = 4, FName = "Kathy", DOB = DateTime.Parse("11/15/1976")});

        empList.Add(new Employee() { ID = 5, FName = "Lena",  DOB = DateTime.Parse("05/11/1978")});

 

        var records = from emp in empList

                      select emp;

        var pgNo = 1;

        var pgRec = 2;

        records = records.Skip((pgNo - 1) * pgRec).Take(pgRec);

 

        foreach (var r in records)

        {

            Console.WriteLine(r.FName);

        }

 

    }

 

    class Employee

    {

        public int ID { get; set; }

        public string FName { get; set; }

        public DateTime DOB { get; set; }

    }

 

}

VB.NET

Imports System

Imports System.Collections.Generic

Imports System.Linq

Imports System.Web

Imports System.Web.UI

Imports System.Web.UI.WebControls

 

Partial Public Class LINQ

    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

        Dim empList As New List(Of Employee)()

        empList.Add(New Employee() With {.ID = 1, .FName = "John", .DOB = DateTime.Parse("12/11/1971")})

        empList.Add(New Employee() With {.ID = 2, .FName = "Mary", .DOB = DateTime.Parse("01/17/1961")})

        empList.Add(New Employee() With {.ID = 3, .FName = "Amber", .DOB = DateTime.Parse("12/23/1971")})

        empList.Add(New Employee() With {.ID = 4, .FName = "Kathy", .DOB = DateTime.Parse("11/15/1976")})

        empList.Add(New Employee() With {.ID = 5, .FName = "Lena", .DOB = DateTime.Parse("05/11/1978")})

 

        Dim records = _

         From emp In empList _

         Select emp

        Dim pgNo = 1

        Dim pgRec = 2

        records = records.Skip((pgNo - 1) * pgRec).Take(pgRec)

 

        For Each r In records

            Console.WriteLine(r.FName)

        Next r

 

    End Sub

 

    Private Class Employee

        Private privateID As Integer

        Public Property ID() As Integer

            Get

                Return privateID

            End Get

            Set(ByVal value As Integer)

                privateID = value

            End Set

        End Property

        Private privateFName As String

        Public Property FName() As String

            Get

                Return privateFName

            End Get

            Set(ByVal value As String)

                privateFName = value

            End Set

        End Property

        Private privateDOB As DateTime

        Public Property DOB() As DateTime

            Get

                Return privateDOB

            End Get

            Set(ByVal value As DateTime)

                privateDOB = value

            End Set

        End Property

    End Class

 

End Class

Observe how we have used the Skip and Take function on the List.

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About The Author

Suprotim Agarwal, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.