public double Sumar_Valores_de_Campos(string sqlsum) { double res = 0; OdbcDataReader dr = null; if (conexion.State == ConnectionState.Open) { conexion.Close(); } conexion.Open(); try { dr = new OdbcCommand(sqlsum, conexion).ExecuteReader(); if (dr.HasRows) { dr.Read(); if (dr.IsDBNull(0)) { res = 0; } else { res = Convert.ToDouble(dr.GetValue(0)); } } //if (Convert.ToDouble(new OdbcCommand(sqlsum, conexion).ExecuteScalar()) >= 0) //{ // res = Convert.ToDouble(new OdbcCommand(sqlsum, conexion).ExecuteScalar()); //} //else //{ // res = 0; //} } catch (Exception ex) { res = 0; MessageBox.Show("Error al momento de realizar la suma de valores de la Data Base: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } finally { dr.Close(); } return(res); }