Implementing Paging in a Generic List using LINQ




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, ASP.NET Architecture MVP works as an Architect Consultant and provides consultancy on how to design and develop Web applications.

Suprotim is also the founder and primary contributor to DevCurry, DotNetCurry and SQLServerCurry. He has also written an EBook 51 Recipes using jQuery with ASP.NET Controls.

Follow him on twitter @suprotimagarwal

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