Sounds like you are talking about FAYT - find as you type
This is a simple bit of code I use for a combo. Gets more complicated if you want to use in a textbox to apply to a form because of losing focus.
Code:
Private Sub cboCustomer_Change()
Static Txt As String
With cboCustomer
.RowSource = Replace(Replace(.RowSource, "'*" & Txt & "*'", "'*" & .Text & "*'"),"Not ","")
.Dropdown
End With
End Sub
two things you need to do
1. set the combo Auto Expand property to No
2. include in your rowsource a criteria for the field in the combo column(1) something like 'SELECT ID, Name FROM myTable WHERE Name Not Like '**' ORDER BY Name'
This will not load any data into the combo until the user has entered a character, when they do, the replace function removes the Not