How to Select & Deselect Multiple Checkbox in Gridview

Gridview Select Multiple Checkbox in ASP.NET

HTML Markup : Add Gridview to WebPage

 <asp:GridView ID="grdview1" runat="server" AutoGenerateColumns="False" 
        onrowdatabound="grdview1_RowDataBound" BackColor="White" 
        BorderColor="#999999" BorderStyle="Solid" BorderWidth="1px" CellPadding="3" 
        ForeColor="Black" GridLines="Vertical">
        <AlternatingRowStyle BackColor="#CCCCCC" />
     <Columns>     
      <asp:TemplateField>
       <HeaderTemplate>
         <asp:CheckBox ID="chk_parent_grdview" runat="server" />
       </HeaderTemplate>
       <ItemTemplate>
        <asp:CheckBox ID="chk_child_grdview" runat="server" />
       </ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField HeaderText="Book ID">
       <ItemTemplate>
        <asp:Label ID="lbl_bookid" runat="server" Text='<%# Evalundefined"Book_Id") %>'></asp:Label>
       </ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField  HeaderText="Book Name">
       <ItemTemplate>
       <asp:Label ID="lbl_bookname" runat="server" Text='<%# Evalundefined"Book_name") %>'></asp:Label>
       </ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField  HeaderText="Book Author">
       <ItemTemplate>
        <asp:Label ID="lbl_bookauthor" runat="server" Text='<%# Evalundefined"Book_author") %>'></asp:Label>
       </ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField  HeaderText="Book Publisher Name">
       <ItemTemplate>
        <asp:Label ID="lbl_bookpubname" runat="server" Text='<%# Evalundefined"Book_Publisher_name") %>'></asp:Label>
       </ItemTemplate>
      </asp:TemplateField>
     </Columns>
        <FooterStyle BackColor="#CCCCCC" />
        <HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
        <PagerStyle BackColor="#999999" ForeColor="Black" HorizontalAlign="Center" />
        <SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
        <SortedAscendingCellStyle BackColor="#F1F1F1" />
        <SortedAscendingHeaderStyle BackColor="#808080" />
        <SortedDescendingCellStyle BackColor="#CAC9C9" />
        <SortedDescendingHeaderStyle BackColor="#383838" />
    </asp:GridView>

Add Javascript to WebPage

<script type="text/javascript">
    function SelectAll(id) {
        var grid = document.getElementById("<%= grdview1.ClientID %>");
        var cell;        
        if (grid.rows.length > 0) {
            for (i = 1; i < grid.rows.length; i++) {
                cell = grid.rows[i].cells[0];                
                for (j = 0; j < cell.childNodes.length; j++) {
                    if (cell.childNodes[j].type == "checkbox") {
                        cell.childNodes[j].checked = document.getElementById(id).checked;
                    }
                }
            }
        }
    }
    </script>

C# Coding

C# Coding : Namespace

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

C# Coding : Page Load

public partial class _Default : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ms"].ConnectionString);
    SqlDataAdapter da;
    DataSet ds = new DataSet();
    protected void Page_Load(object sender, EventArgs e)
    {
        FillGrdView();
    }

C# Coding : Gridview

    private void FillGrdView()
    {
        da = new SqlDataAdapter("Select * from Book", con);
        da.Fill(ds);
        if (ds.Tables[0].Rows.Count > 0)
        {
            grdview1.DataSource = ds;
            grdview1.DataBind();
        }
        
    }
    protected void grdview1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        //header select all function
        if (e.Row.RowType == DataControlRowType.Header)
        {
            ((CheckBox)e.Row.FindControl("chk_parent_grdview")).Attributes.Add("onclick", "javascript:SelectAll('" + ((CheckBox)e.Row.FindControl("chk_parent_grdview")).ClientID + "')");            
        }
    }
}