如何才能保持它被记录在数据库中的变量之前,我更新了它的价值?我想为一个新的价值运作的旧值,
例如:
NewValue - OldValue = VariableValue
230 - 200 = 30,
的方式的的OldValue是NewValue之前我更新。
可以给我一个关于它的主意,如果可能的话。
private void ChargerKiloVoitures()
{
try {
_bd.Command.CommandText = "SELECT Kilometrage FROM Voitures " +
"WHERE NumeroMatricule = \"" + CBNumMatricule.Text + "\"";
Debug.WriteLine( Environment.NewLine );
Debug.WriteLine( _bd.Command.CommandText );
_bd.Reader = _bd.Command.ExecuteReader();
if ( _bd.Reader.Read());
this.analogCounter2.Number = int.Parse(_bd.Reader["Kilometrage"].ToString());
this.analogCounter1.Number = this.analogCounter2.Number + VidangeConstant;
//i have problem here exactly
int OldKilometrage = int.Parse(_bd.Reader["Kilometrage"].ToString());
int NewKilometrage = int.Parse(_bd.Reader["Kilometrage"].ToString());
KiloMetrag.Value = NewKilometrage-OldKilometrage;
}//if
_bd.Reader.Close();
}//try
catch (Exception ex) {
Debug.WriteLine( Environment.NewLine );
Debug.WriteLine( ex.Message );
MessageBox.Show("Une erreur a 茅t茅 d茅tect茅e : " + Environment.NewLine + ex.Message, "Erreur");
}//catch
}