script language="javascript" type="text/javascript"
function click() 
{
return confirm("Are u sure u want to delete this record");
} 

asp:GridView ID="GridView1" runat="server" 
onpageindexchanging="GridView1_PageIndexChanging" 
onrowcancelingedit="GridView1_RowCancelingEdit" 
onrowediting="GridView1_RowEditing" 
onrowupdating="GridView1_RowUpdating" AutoGenerateColumns="False" 
DataKeyNames="ID"

PagerSettings FirstPageText="Next" LastPageText="Previous" 
NextPageText="Next" PreviousPageText="Previous" Mode="NumericFirstLast"

Columns
asp:TemplateField
ItemTemplate
asp:CheckBox ID="chk" runat="server" 

ItemTemplate 
asp:TemplateField
asp:CommandField ShowEditButton="True" 
asp:BoundField DataField="NAME" HeaderText="Name" 
asp:BoundField DataField="NUMBER" HeaderText="Number" 
asp:BoundField DataField="Total" HeaderText="Tasks"
Columns

asp:GridView

asp:Button ID="delete" runat="server" Text="Delete" onclick="delete_Click" OnClientClick="javascript:returnclick();"

using System.Data.Sql;
using System.Data.SqlClient;

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
bind();
}
}

public void bind()
{
SqlConnection con=new SqlConnection(@"server=xx;dbname=xx;user id=xx;password=xx");
SqlCommand cmd=new SqlCommand("Select * from tablename",con);
SqlDataAdpter ada=new SqlDataAdpter(cmd);
DataSet ds=new DataSet();
con.Open();
ada.Fill(ds);
con.Close();
gridView1.DataSource=ds;
gridView1.DataBind();
}

protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
GridView1.EditIndex = e.NewEditIndex;
bind();
}

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
TextBox Name;
TextBox Number;
TextBox total;

int id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value); 
Name =(TextBox)GridView1.Rows[e.RowIndex].Cells[2].Controls[0];
Number = (TextBox)GridView1.Rows[e.RowIndex].Cells[3].Controls[0];

str = "update tbname set NAME='" + Name.Text + "',NUMBER="+Number.Text+" where ID="+id+"";
inserttotable(str); 
GridView1.EditIndex = -1;
bind();
Response.Write("Data get updated successfully"); 
}

protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
GridView1.EditIndex = -1;
bind();
}

protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
bind();
}

protected void delete_Click(object sender, EventArgs e)
{
foreach (GridViewRow row in GridView1.Rows)
{
CheckBox checkbox = (CheckBox)row.FindControl("chk");
if (checkbox.Checked)
{
int no = Convert.ToInt32(GridView1.DataKeys[row.RowIndex].Value);
str = "delete from tbname where ID="+no+"";
}
}
bind();
}

public void inserttotable(string str)
{
con.open();
cmd = new SqlCommand(str, con);
cmd.ExecuteNonQuery();
con.close();
}