Hi,
   i am trying the code for deleting records in the gridview, but after selecting ckeckbox and clicking on delete button all the rows data is getting deleted, i wanted to delete only check box marked row data. i am not getting what mistake i have did. my sample code is shown below.
  my .aspx code is
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default3.aspx.cs" Inherits="Default3" Debug="true"%>
<!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:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" CellPadding="4"
DataKeyNames="cat_id" ForeColor="#333333" GridLines="None" OnRowCancelingEdit="GridView1_RowCancelingEdit"
OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating">
<FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
<Columns>
<asp:TemplateField>
                    <HeaderTemplate>
                        <asp:Button ID="btnDelete" runat="server" Text="Delete"/>
                    </HeaderTemplate>
                    <ItemTemplate>
                        <asp:CheckBox ID="CheckBox1" runat="server" />
                    </ItemTemplate>
                </asp:TemplateField>
<asp:CommandField HeaderText="Edit-Update" ShowEditButton="True" />
<asp:BoundField DataField="cat_id" HeaderText="Category ID" ReadOnly="True" />
<asp:BoundField DataField="cat_name" HeaderText="Category Name" />
<asp:BoundField DataField="Location" HeaderText="Location" />
<asp:BoundField DataField="Date" HeaderText="Date" />
</Columns>
<RowStyle BackColor="#E3EAEB" />
<EditRowStyle BackColor="#7C6F57" />
<SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
<PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
<HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>
        <asp:Button ID="Button1" runat="server" Text="Add New Row" 
            onclick="Button1_Click" />
                                               
            <asp:Button ID="btnDelete" runat="server" OnClick="btnDelete_Click" Text="Delete Selected Records" />
    </div>
    </form>
</body>
</html>
and my .aspx.cs code is
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.Collections.Specialized;
using System.Text;
using System.Collections;
public partial class Default3 : System.Web.UI.Page
{
     SqlConnection con = new SqlConnection();
    SqlCommand cmd = new SqlCommand();
    string connectionString = "Data Source=hobvision07;Initial Catalog=master; user id=sa;password=hobvision";
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            BindData();
            
            btnDelete.Attributes.Add("onclick",
         "return confirm('Are you sure you want to delete selected item(s) ?');");
        }
    }
    private void BindData()
    {
        SqlConnection con = new SqlConnection("Data source=hobvision07; initial catalog=master; user id=sa; password=hobvision");
        SqlDataAdapter da = new SqlDataAdapter("SELECT cat_id, cat_name,location,date FROM quest_categories", con);
        DataTable dt = new DataTable();
        da.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection("Data source=hobvision07; initial catalog=master; user id=sa; password=hobvision");
        SqlDataAdapter da = new SqlDataAdapter("SELECT cat_id, cat_name,location,date FROM quest_categories", con);
        DataTable dt = new DataTable();
        da.Fill(dt);
        // Here we'll add a blank row to the returned DataTable
        DataRow dr = dt.NewRow();
        dt.Rows.InsertAt(dr, 0);
        //Creating the first row of GridView to be Editable
        GridView1.EditIndex = 0;
        GridView1.DataSource = dt;
        GridView1.DataBind();
        //Changing the Text for Inserting a New Record
        ((LinkButton)GridView1.Rows[0].Cells[1].Controls[0]).Text = "Insert";
    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        BindData();
    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        BindData();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        if (((LinkButton)GridView1.Rows[0].Cells[1].Controls[0]).Text == "Insert")
        {
            SqlConnection con = new SqlConnection("Data source=hobvision07; initial catalog=master; user id=sa; password=hobvision");
            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "INSERT INTO quest_categories(cat_name,location,date) VALUES(@cat_name,@location,@date)"; cmd.Parameters.Add("@cat_name", SqlDbType.VarChar).Value = ((TextBox)GridView1.Rows[0].Cells[3].Controls[0]).Text;
            cmd.Parameters.Add("@location", SqlDbType.VarChar).Value = ((TextBox)GridView1.Rows[0].Cells[4].Controls[0]).Text;
            cmd.Parameters.Add("@date", SqlDbType.VarChar).Value = ((TextBox)GridView1.Rows[0].Cells[5].Controls[0]).Text;
            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
        else
        {
            SqlConnection con = new SqlConnection("Data source=hobvision07; initial catalog=master; user id=sa; password=hobvision");
            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "UPDATE quest_categories SET cat_name=@cat_name,location=@location,date=@date WHERE cat_id=@cat_id";
            cmd.Parameters.Add("@cat_name", SqlDbType.VarChar).Value = ((TextBox)GridView1.Rows[e.RowIndex].Cells[3].Controls[0]).Text;
            cmd.Parameters.Add("@location", SqlDbType.VarChar).Value = ((TextBox)GridView1.Rows[e.RowIndex].Cells[4].Controls[0]).Text;
            cmd.Parameters.Add("@date", SqlDbType.VarChar).Value = ((TextBox)GridView1.Rows[e.RowIndex].Cells[5].Controls[0]).Text;
            cmd.Parameters.Add("@cat_id", SqlDbType.Int).Value = Convert.ToInt32(GridView1.Rows[e.RowIndex].Cells[2].Text);
            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
        GridView1.EditIndex = -1;
        BindData();
    }
   
    protected void btnDelete_Click(object sender, EventArgs e)
    {
        ArrayList productsToDelete = new ArrayList();
        foreach (GridViewRow row in GridView1.Rows)
        {
            if (row.RowType == DataControlRowType.DataRow)
            {
                CheckBox chkDelete = (CheckBox)row.Cells[0].FindControl("chkDelete");
                if (chkDelete != null)
                {
                    if (chkDelete.Checked)
                    {
                        string productId = row.Cells[1].Text;
                        productsToDelete.Add(productId);
                    }
                }
            }
        }
        DeleteProducts(productsToDelete);
        BindData();
    }
    private void DeleteProducts(ArrayList productsToDelete)
    {
       
        foreach (GridViewRow row in GridView1.Rows)
        {
            
            string productId = row.Cells[2].Text;
            SqlConnection con = new SqlConnection("Data source=hobvision07; initial catalog=master; user id=sa; password=hobvision");
            SqlDataAdapter cmd = new SqlDataAdapter("delete from quest_categories where cat_id='" + productId + "'", con);
            DataTable dt = new DataTable();
            cmd.Fill(dt);
            GridView1.DataSource = dt;
            GridView1.DataBind();
            
            //BindData();
        }
      }
   }
Please help me regarding this.