combo box

[mheiy]

how can i automatically add a new number when i click the combo box.

example my inside my combo box i have a course of NURSING, IT, Engineering
then i choose Nursing the txtBatchNUm will automatically generate NUR-0002.
hope anyone can help....

Private Sub cmdSave_Click()
   With tbCourse
           .MoveFirst
            .Find "BatchNumber = '" & txtBatchNum & "'"
            If .Fields(2) = txtBatchNum Then
                MsgBox "Batch Number Already Exist.", vbInformation, "Titus School of Multimedia"
                txtBatchNum = ""
                txtBatchNum.SetFocus
            ElseIf .EOF = True Then
                .AddNew
                AddFields
                MsgBox "Batch Number successfully saved to the record.", vbInformation, "Titus School of Multimedia"
                .Update
                .Requery
                txtBatchNum = ""
                cmbCourse.Clear
                cmbDepartment.Clear
                txtNoSeat = ""
             End If
        End With
End Sub
 
Private Sub Form_Load()
With tbCourse
 If .BOF = True And .EOF = True Then
        Refresh
    Else
        Do Until .EOF
            cmbCourse.AddItem (.Fields(0))
            .MoveNext
        Loop
    End If
End With
 
With tbDepartment
 If .BOF = True And .EOF = True Then
        Refresh
    Else
        Do Until .EOF
            cmbDepartment.AddItem (.Fields(0))
           .MoveNext
        Loop
    End If
End With
 
End Sub
 
Private Sub AddFields()
 
With tbBatch
    .Fields(0) = cmbCourse
    .Fields(1) = txtNoSeat
    .Fields(2) = txtBatchNum
    .Fields(3) = cmbDepartment
End With
 
End Sub