Actually I'm doubted about something. the value of dateTimepicker include date and time. but a DATE format in Access is pure date.
Mabe i should somehow filter the value of dateTimePicker to extract date part of that.
here is related parts of my code:
queryString = "INSERT INTO ProductSubjects (PSCode, PSName, PSDescription, CustomerID, , PSBeginDate, PSEndDate) " +
"VALUES (? , ? , ? , ? , ? , ?)";
OleDbParameter p1 = new OleDbParameter();
command.Parameters.Add(p1);
p1.Value = ps + code.ToString();
.
.
.
OleDbParameter p5 = new OleDbParameter();
command.Parameters.Add(p5);
p5.Value = dateTimePicker1.Value;
OleDbParameter p6 = new OleDbParameter();
command.Parameters.Add(p6);
p6.Value = dateTimePicker2.Value;
command.CommandText = queryString;
Int32 records = command.ExecuteNonQuery();