Lets Imagine together that we create a table in the DataBase

Called(My Table)and it has Two Fields,The First one Is a primary Field called(The Code),and the second Field called(Name)..
-------------------------------------
The Code Name
-------------------------------------
1 Ahmed
2 OLA
3 Kholoud
4 Tom
5 Adam
--------------------------------------
In the Form_Load()Event ..Lets Fill Combo1 with the above Names

Private Sub Form_Load()

Dim Rs as ADODB.Recordset

set Rs=new Recordset

Rs.Open "MyTable",Con-------->>Con is refer to Connection Object.

Rs.MoveFirst

Do Until Rs.Eof

Combo1.addItem Rs.fields("Name").value---->>Fill the Combo1 with the ----Values of this Field.
Combo1.ItemData(Combo1.NewIndex)=Rs.Fields("The Code").value

Rs.moveNext

Loop

End Sub
*******
In the Combo1_Click()Event

Private Sub Combo1_Click() event

Dim Val

Val=Combo1.ItemData(Combo1.ListIndex).value

End Sub

-->>Now this Val Refer to the Value of((The Code))Field

Hope I could Make it More Clear now..

Have Good Luck again..Bye