How to delete record in gridview

use template field and pass id as CommandArgument

<asp:templatefield xmlns:asp="#unknown">
                 <itemtemplate>
                 <asp:linkbutton id="lb1" runat="server" causesvalidation="false" onclientclick="return confirm('Are You sure to delete this entry')" text="Delete" commandargument="<%#Eval("id")%>"></asp:linkbutton>
                 </itemtemplate>
                 
                 </asp:templatefield>

and on row command of gridview

protected void rowcmd(object sender, GridViewCommandEventArgs e)
   {
     // create and open DB connection
       try
       {
           //int index = Convert.ToInt32(e.CommandArgument);
           //GridViewRow row = GridView1.Rows[index];
           Int32 id = Convert.ToInt32(e.CommandArgument);
           string comm = "Delete from tblComments where id=@id";
           SqlCommand cmd = new SqlCommand(comm, Db.GetConnection());
           cmd.Parameters.AddWithValue("id", id);
           cmd.ExecuteNonQuery();
           //ClientScript.RegisterStartupScript
           //(GetType(), "Javascript", "javascript: return alert('Deleted');; ", true);
           GridView1.DataBind();
       }
       catch (Exception ex)
       {
       }

   }

hello dear,

in your gridview , when you click on the delete button (if i.e. auto generated column) get the id of that row means unique id of that row.
If there is no unique id then bind it in hidden field. and get that id on the click event of delete button. and execute delete query. like this :

string str = GridView1.DataKeys[e.NewSelectedIndex].Value.ToString();
SqlCommand cmd = new SqlCommand("delete from tablename where id=@id", con);
cmd.Parameters.AddWithValue("@id", str);
con.Open();
cmd.ExecuteNonQuery();
con.Close();

and bind grid again.

Hope this will help you.
And Don't forget to mark as answer if it helps. :)