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Load More Records in ASP.NET Gridview on Button Click from SQL Server Table

, 1 Jun 2014 CPOL
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In this article, I am going to demonstrate how to get more data on demand i.e. On every click of button fetch more records from SQL Server database table and load in GridView with wait/progress/loading image as shown in image in ASP.NET using both C# and VB languages.

Introduction

Basically you will learn the following through this article:

  • How to initially bind specified number of records from SQL Server database table to Gridview.
  • How to bind some data in Gridview and on every click of "Load More Databutton" fetch more data and load in Gridview.
  • How to show wait/progress loading image using Ajax "UpdateProgress" and "ProgressTemplate" while fetching more data from SQL Server table and binding to gridview.

Using the Code

Implementation: Let's create a demo website to demonstrate the concept.

First of all, create a database in SQL Server and name it, e.g. "DB_Student" and in this database, create a table with the following Columns and Data type as shown below and name this table "Tbl_Student".

Column Name Data Type
StudentId Int(Primary Key. So set is identity=true)
StudentName varchar(100)
Class varchar(50)
Age Int
Gender varchar(50)
Address varchar(500)

Create a stored procedure to get student details to be filled in GridView Data Control.

CREATE  PROCEDURE [dbo].[GetStudentDetails_SP]
                @topVal INT
AS
BEGIN
--if @topVal=2 then the below query will become SELECT top (2) * FROM dbo.Tbl_Student and get 2 records
                SELECT top (@topVal) * FROM dbo.Tbl_Student
END

Create another stored procedure to count the number of rows present in table:

CREATE PROCEDURE [dbo].[GetStudentDetailsCount_SP]             
AS
BEGIN
                SELECT COUNT(*) FROM dbo.Tbl_Student
END 

Now let's connect our ASP.NET application with SQL Server database.

So in the <configuration> tag of web.config file, create the connection string as:

<connectionStrings>
    <add name="conStr" connectionString="Data Source=LALIT;_
    Initial Catalog=DB_Student;Integrated Security=True"/>
  </connectionStrings>

Note: Replace the Data Source and Initial Catalog as per your database settings.

ASP.NET C# Section

Below is the HTML source of the Default.aspx page.

<%@ Page Language="C#" AutoEventWireup="true" 
CodeFile="Default.aspx.cs"Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>       
<fieldset style="width:370px;">
    <legend>Load more data on demand in GridView</legend>
    <table>
    <tr>
    <td>
     <asp:GridView ID="grdStudentDetails" runat="server" AutoGenerateColumns="False"
            CellPadding="4" ForeColor="#333333" GridLines="None">
         <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
        <Columns>
        <asp:BoundField HeaderText="Student Name"  DataField="StudentName" />
        <asp:BoundField HeaderText="Class"  DataField="Class" />
        <asp:BoundField HeaderText="Age"  DataField="Age" />
        <asp:BoundField HeaderText="Gender"  DataField="Gender" />
        <asp:BoundField HeaderText="Address"  DataField="Address" />    
        </Columns>
         <EditRowStyle BackColor="#999999" />
         <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
         <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
         <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
         <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
         <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
         <SortedAscendingCellStyle BackColor="#E9E7E2" />
         <SortedAscendingHeaderStyle BackColor="#506C8C" />
         <SortedDescendingCellStyle BackColor="#FFFDF8" />
         <SortedDescendingHeaderStyle BackColor="#6F8DAE" />
        </asp:GridView>        
    </td>
    </tr>
    <tr>
    <td align="center">
        <asp:Button ID="btnLoadMore" runat="server" Text="Load More Data"
            onclick="btnLoadMore_Click" />
            </td>
            </tr>
            <tr>
            <td align="center">
            <asp:UpdateProgress ID="UpdateProgress1" runat="server" 
            ClientIDMode="Static"DisplayAfter="10">
    <ProgressTemplate>
        <img src="ajax-loader.gif" alt="wait image" />   
    </ProgressTemplate>
    </asp:UpdateProgress>
            </td></tr>
    </table>
    </fieldset>
    </ContentTemplate>   
        </asp:UpdatePanel>   
    </div>
    </form>
</body>
</html>

Note: You need to search on the internet and download any wait/progress GIF image of your choice and name it "ajax-loader.gif" and paste in root folder of your project.

ASP.NET C# Code Section

In code behind file (default.aspx.cs), write the code as:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public partial class _Default: System.Web.UI.Page
{ 
    SqlConnection con = newSqlConnection(ConfigurationManager.ConnectionStrings["conStr"].ConnectionString);

   int num = 0;

protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
          //Set the num variable equal to the value that you want to load data in GridView.
          //e.g if initially you want to load 2 rows in Gridview then set num=2.
            num = 2;
          //Store this num variable value in ViewState so that we can get this value on Load more button click
            ViewState["num"]=num;
            BindGridView(num);
        }
    }

    private void BindGridView(int numOfRows)
    {
        DataTable dt = new DataTable();
        SqlCommand cmd = null;
        SqlDataAdapter adp = null;
        try
        {
            //get number rows in table by calling the rowCount function i created.
            int rCount = rowCount();

            // hide the "Load More Data button" if the number of requested rows becomes greater than the rows in table
            if (numOfRows > rCount)
            {
                btnLoadMore.Visible = false;
            }
            cmd = new SqlCommand("GetStudentDetails_SP", con);

            //Passs numOfRows variable value to stored procedure to get desired number of rows

            cmd.Parameters.AddWithValue("@topVal", numOfRows);
            cmd.CommandType = CommandType.StoredProcedure;
            adp = new SqlDataAdapter(cmd);
            adp.Fill(dt);

            if (dt.Rows.Count > 0)
            {
                grdStudentDetails.DataSource = dt;
                grdStudentDetails.DataBind();
            }
            else
            {
                grdStudentDetails.DataSource = null;
                grdStudentDetails.DataBind();
            }
        }
        catch (Exception ex)
        {
            ScriptManager.RegisterStartupScript(this, this.GetType(), "Message", 
            "alert('Oops!! Error occured: " + ex.Message.ToString() + "');", true);
        }
        finally
        {
            con.Close();
            cmd.Dispose();
            adp = null;
            dt.Clear();
            dt.Dispose();
        }
    }

    protected int rowCount()
    {
        int NoOfRows = 0;
        SqlCommand cmd = new SqlCommand("GetStudentDetailsCount_SP", con);
        cmd.CommandType = CommandType.StoredProcedure;

        try
        {
            con.Open();
            NoOfRows = Convert.ToInt32(cmd.ExecuteScalar());
        }
        catch (Exception ex)
        {
            ScriptManager.RegisterStartupScript(this, this.GetType(), "Message", 
            "alert('Oops!! Error occured: " + ex.Message.ToString() + "');", true);
        }
        finally
        {
            con.Close();
            cmd.Dispose();
        }
        return NoOfRows;
    }

    protected void btnLoadMore_Click(object sender, EventArgs e)
    {
        //On every click of this button it will add 2 to the ViewState["num"]
        //whose value was set to 2 initially on page load. So numval is 4 now.

        int numVal = Convert.ToInt32(ViewState["num"])+ 2;

        //Now pass numVal whose value is 4 to the BindGridView function to get 4 rows.

        BindGridView(numVal);

        //Set ViewState["num"] equal to the numVal i.e. 4 so that 
        //when we again click this button it will be 4 + 2= 6 and so on.

        ViewState["num"]= numVal;
    }
}

ASP.NET VB Section

Design the page (default.aspx) as in above ASP.NET C# section, but replace the lines:

<asp:Button ID="btnLoadMore" runat="server" Text="Load More Data"
onclick="btnLoadMore_Click" />

with the following line:

<asp:Button ID="btnLoadMore" 
runat="server" Text="Load More Data" />

In the code behind file (e.g. default.aspx.vb), write the code as:

Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration

Partial Class _Default
    Inherits System.Web.UI.Page

    Dim con As NewSqlConnection(ConfigurationManager.ConnectionStrings("conStr").ConnectionString)

    Dim num As Integer = 0


Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load

        If Not Page.IsPostBack Then
            'Set the num variable equal to the value that you want to load data in gridView
            'e.g if initially you want to load 2 rows in GridView then set num=2.

            num = 2

            'Store this num variable value in ViewState so that we can get this value on Load More Data button click

            ViewState("num")=2
            BindGridView(num)
        End If
    End Sub


    Private Sub BindGridView(numOfRows As Integer)
        Dim dt As New DataTable()
        Dim cmd As SqlCommand = Nothing
        Dim adp As SqlDataAdapter = Nothing

        Try
            'get number rows in table by calling the rowCount function i created.
            Dim rCount As Integer = rowCount()

            'hide the "Load More Data button" 
            'if the number of requested rows becomes greater than the rows in table

            If numOfRows > rCount Then
                btnLoadMore.Visible = False
            End If

            cmd = New SqlCommand("GetStudentDetails_SP", con)

            'Passs numOfRows variable value to stored procedure to get desired number of rows

            cmd.Parameters.AddWithValue("@topVal", numOfRows)
            cmd.CommandType = CommandType.StoredProcedure
            adp = New SqlDataAdapter(cmd)
            adp.Fill(dt)

            If dt.Rows.Count > 0 Then
                grdStudentDetails.DataSource = dt
                grdStudentDetails.DataBind()
            Else
                grdStudentDetails.DataSource = Nothing
                grdStudentDetails.DataBind()
            End If
        Catch ex As Exception
            ScriptManager.RegisterStartupScript(Me, Me.[GetType](), "Message", _
            "alert('Oops!! Error occured: " + ex.Message.ToString() + "');", True)

        Finally
            con.Close()
            cmd.Dispose()
            adp = Nothing
            dt.Clear()
            dt.Dispose()
        End Try
    End Sub

    Protected Function rowCount() As Integer
        Dim NoOfRows As Integer = 0
        Dim cmd As New SqlCommand("GetStudentDetailsCount_SP", con)
        cmd.CommandType = CommandType.StoredProcedure

        Try
            con.Open()
            NoOfRows = Convert.ToInt32(cmd.ExecuteScalar())
        Catch ex As Exception
            ScriptManager.RegisterStartupScript(Me, Me.[GetType](), "Message", _
            "alert('Oops!! Error occured: " + ex.Message.ToString() + "');", True)

        Finally
            con.Close()
            cmd.Dispose()
        End Try
        Return NoOfRows
    End Function

    Protected Sub btnLoadMore_Click(sender As Object, e As System.EventArgs) HandlesbtnLoadMore.Click

        'On every click of this button it will add 2 to the ViewState("num") 
        'whose value was set to 2 initially on page load. So numval is 4 now.

        Dim numVal As Integer = Convert.ToInt32(ViewState("num")) + 2

        'Now pass numVal whose value is 4 to the BindGridView function to get 4 rows.

        BindGridView(numVal)

        'Set ViewState("num") equal to the numVal i.e. 4 so that 
        'when we again click this button it will be 4 + 2= 6 and so on.

        ViewState("num") = numVal
    End Sub
End Class

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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Webcodeexpert.com
Software Developer (Senior) www.webcodeexpert.com
India India
I am a passionate programmer and a Software Engineer love blogging and developing applications in Microsoft Technologies.
I have a blog http://www.webcodeexpert.com/
It is a collection of code snippets for web programmers, including code for Asp.Net, Sql Server, C#.Net, VB.Net, Ajax,LINQ, Jquery, JavaScript, XML, WCF Services, C, C++, Interview Questions and answers and more!

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GeneralMy vote of 5 Pin
Heriberto Lugo13-Jul-14 6:27
memberHeriberto Lugo13-Jul-14 6:27 
GeneralRe: My vote of 5 Pin
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memberThanhTrungDo4-Jun-14 19:12 
GeneralRe: My vote of 3 Pin
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memberWebcodeexpert.com5-Jun-14 5:01 
GeneralRe: My vote of 3 Pin
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