Sorting in grid view using Generic List

Sorting in grid view using Generic List

In this example we create a class student and bind grid view using generic list of student type and add storing on generic list to bind grid view.

Student.cs

using System.Collections.Generic;
/// <summary>
/// Summary description for Student
/// </summary>
public class Student
{
    public Student()
    {
        //
        // TODO: Add constructor logic here
        //
    }
    public string RollNo { get; set; }
    public string StudentName { get; set; }
    public List<Student> GetStudentList()
    {
        List<Student> lstStudent = new List<Student>();
        Student objStudent1 = new Student();
        objStudent1.RollNo = "23";
        objStudent1.StudentName = "Ravi Shrivastav";
        lstStudent.Add(objStudent1);
        Student objStudent2 = new Student();
        objStudent2.RollNo = "46";
        objStudent2.StudentName = "Nitin Kumar";
        lstStudent.Add(objStudent2);
        Student objStudent3 = new Student();
        objStudent3.RollNo = "37";
        objStudent3.StudentName = "Neha Gupta";
        lstStudent.Add(objStudent3);
        Student objStudent4 = new Student();
        objStudent4.RollNo = "36";
        objStudent4.StudentName = "Markandey Pathak";
        lstStudent.Add(objStudent4);
        Student objStudent5 = new Student();
        objStudent5.RollNo = "56";
        objStudent5.StudentName = "Rahul Porwal";
        lstStudent.Add(objStudent5);
        Student objStudent6 = new Student();
        objStudent6.RollNo = "40";
        objStudent6.StudentName = "Piyush Pandey";
        lstStudent.Add(objStudent6);
        return lstStudent;
    }
}

Default.aspx

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
    CodeFile="Default.aspx.cs" Inherits="_Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <h2>Sorting in GridView using list</h2>
    <div style="font-size: 14px; color: #000;">
        <asp:GridView ID="gdvStudent" runat="server"
            AllowSorting="true"
            AutoGenerateColumns="false" OnSorting="gdvStudent_Sorting" Width="300px">
            <Columns>
                <asp:BoundField DataField="RollNo" HeaderText="Roll No" SortExpression="RollNo" />
                <asp:BoundField DataField="StudentName" HeaderText="Student Name" SortExpression="StudentName" />
            </Columns>
        </asp:GridView>
    </div>
</asp:Content>

Default.aspx.cs 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.UI.WebControls;
using System.Reflection;
public partial class _Default : System.Web.UI.Page
{
    List<Student> lstStudent = null;
    Student objStudent = new Student();
    protected void Page_Load(object sender, EventArgs e)
    {
        lstStudent = objStudent.GetStudentList();
        if (!IsPostBack)
        {
            gdvStudent.DataSource = lstStudent;
            gdvStudent.DataBind();
        }
    }
    /// <summary>
    /// Gridview sorting event
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void gdvStudent_Sorting(object sender, GridViewSortEventArgs e)
    {
        string Sortdir = GetSortDirection(e.SortExpression);
        string SortExp = e.SortExpression;
        var list = objStudent.GetStudentList();
        if (Sortdir == "ASC")
        {
            list = Sort<Student>(list, SortExp, SortDirection.Ascending);
        }
        else
        {
            list = Sort<Student>(list, SortExp, SortDirection.Descending);
        }
        this.gdvStudent.DataSource = list;
        this.gdvStudent.DataBind();
    }
    /// <summary>
    /// GEt Sorting direction
    /// </summary>
    /// <param name="column"></param>
    /// <returns></returns>
    private string GetSortDirection(string column)
    {
        string sortDirection = "ASC";
        string sortExpression = ViewState["SortExpression"] as string;
        if (sortExpression != null)
        {
            if (sortExpression == column)
            {
                string lastDirection = ViewState["SortDirection"] as string;
                if ((lastDirection != null) && (lastDirection == "ASC"))
                {
                    sortDirection = "DESC";
                }
            }
        }
        ViewState["SortDirection"] = sortDirection;
        ViewState["SortExpression"] = column;
        return sortDirection;
    }
    /// <summary>
    /// Sort function
    /// </summary>
    /// <typeparam name="TKey"></typeparam>
    /// <param name="list"></param>
    /// <param name="sortBy"></param>
    /// <param name="direction"></param>
    /// <returns></returns>
    public List<Student> Sort<TKey>(List<Student> list, string sortBy, SortDirection direction)
    {
        PropertyInfo property = list.GetType().GetGenericArguments()[0].GetProperty(sortBy);
        if (direction == SortDirection.Ascending)
        {
            return list.OrderBy(e => property.GetValue(e, null)).ToList<Student>();
        }
        else
        {
            return list.OrderByDescending(e => property.GetValue(e, null)).ToList<Student>();
        }
    }
}