public DataTable GetDataTable(string strsql)
        {
            conn=new SqlConnection(cnstr);
            DataTable dttmp = new DataTable();
            SqlDataAdapter adp = new SqlDataAdapter(strsql, conn);


            try
            {
                adp.Fill(dttmp);

            }
            catch (Exception ex)
            {
                
                if (conn.State != ConnectionState.Closed())
                {
                    conn.Close();
                }
            }

            finally
            {
                adp.Dispose();
                return dttmp;
            }
 
        }