Deleting grid row on Button click

protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
	try
	{
	string constr = @"Data Source=SQLEXPRESS2008;Initial Catalog=Database;Integrated Security=True";
	string query = "DELETE FROM Table_Name WHERE 1st_column=@a";
 
	SqlConnection con = new SqlConnection(constr);
	SqlCommand cmd = new SqlCommand();
 
	cmd.Parameters.Add("@a", SqlDbType.Int).Value = Convert.ToInt32(GridView1.Rows[e.RowIndex].Cells[1].Text)";
	cmd.Connection = con;
 
	con.Open();
	cmd.ExecuteNonQuery();
 
	con.Close();
	BindData();
	}
	catch(Exception ex)
	{
	    throw ex;
	}
  }

protected void gvLoad_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
    dt = tblGridRow();
    dt.Rows.RemoveAt(e.RowIndex);
    gvLoad.DataSource = dt;
    gvLoad.DataBind();



}