این کد کجاش اشتباس :
OleDbConnection con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0 ;Data Source=mytable.mdb");
OleDbCommand cmd = new OleDbCommand();
OleDbDataReader dr;
con.Open();
cmd.Connection = con;
dr = cmd.ExecuteReader();
dr.Read();
int menha = int.Parse(dr.GetValue(5).ToString());
menha = menha - 1;
this.Text = menha.ToString();
cmd.CommandText = "UPDATE mytable SET ظرفيت = '" + menha.ToString() + "' WHERE نوع_ماشين = '" + comboBox1.SelectedItem.ToString() + "'";
dr.Close();
con.Close();