Why does Access VBA dropdown method not work? - ms-access

Question

I'm using a text box to filter a combo box list in Access 2013. I put the filter code in the Form_Timer sub so as to give users time to type the entire filter string before applying the filter, and I invoke the timer from the text box Change sub. It works great except for one thing: I want the combo box list to drop down and display results, and it just won't work. However I put the exact same line of code in the GotFocus sub for the combo box, and that line works perfectly.
I also tried executing the filter code within the Change sub, just in case there was some weirdness regarding Form_Timer execution. Same result. Here is the code:
Private Sub cboCENamesMain_GotFocus()
Me.cboCENamesMain.Dropdown '<---This line works perfectly.
End Sub
Private Sub Form_Timer()
Dim strSQL As String
Me.TimerInterval = 0
Me.txtFilter.Value = Me.txtFilter.Text
Me.cboCENamesMain.SetFocus
strSQL = ""
strSQL = strSQL & "Select DISTINCT [CE ID] "
strSQL = strSQL & "From [tblMyTable] "
If Len(Me.txtFilter) > 0 Then
strSQL = strSQL & "Where [CE ID] Like ""*" & Me.txtFilter & "*"" "
End If
strSQL = strSQL & "Order By [CE ID];"
Me.cboCENamesMain.RowSource = strSQL
Me.cboCENamesMain.Dropdown '<---This line doesn't do what it's supposed to.
Me.txtFilter.SetFocus
Me.txtFilter.SelStart = Len(Me.txtFilter.Text)
Me.txtFilter.SelLength = 0
End Sub
Private Sub txtFilter_Change()
If Len(Me.txtFilter.Text) = 0 _
Or Len(Me.txtFilter.Text) > 2 Then
Me.TimerInterval = 500
End If
End Sub
I could use a list box instead of a combo box to allow users to see the results of their filter typing, but that would seriously detract from my form design. I have searched on Google and on StackOverflow, and have not found anybody else discussing this issue. Any ideas?

Answer 1

Here is my final code. This works just the way I want. The user types a few characters, and the timer automatically filters the combo box list down to items containing the typed string.
StackOverflow is a great place to file stuff like this - going from job to job it will save some time reinventing the wheel.
The extensive comments in the code are for the analysts who will need to maintain the applications after my contract ends. Neither of them has ever written VBA.
Private Sub cboCENamesMain_Change()
' Ordinarily the AfterUpdate event would automatically fire off the Change event.
' We set a flag to avoid that - otherwise the list would be filtered to only the selected record.
If booCancelChange = False Then
' Don't bother filtering the combo box list unless the filter text is null or longer than
' 1 character.
If Len(Me.cboCENamesMain.Text) <> 1 Then
' Set the Form_Timer event to fire off in 0.3 second to give them time to type a few characters.
Me.TimerInterval = 300
End If
Else
' Reset the flag, otherwise the Change code would stop working after the first record selection.
booCancelChange = False
End If
End Sub
Private Sub Form_Timer()
Dim strSQL As String
' Reset the timer to not fire off, so that it won't keep running without a change
' in the combo box.
Me.TimerInterval = 0
' If they have tabbed out of the combo box after selecting an item, we don't want to
' do this. It's unnecessary and it throws errors from references to the control's
' properties when focus is no longer on the control.
If Screen.ActiveControl.Name = Me.cboCENamesMain.Name Then
' Create a SQL filter for the combo box using the entered text.
strSQL = ""
strSQL = strSQL & "Select DISTINCT [CE ID] "
strSQL = strSQL & "From [Covered Entities] "
If Len(Me.cboCENamesMain.Text) > 0 Then
strSQL = strSQL & "Where [CE ID] Like ""*" & Me.cboCENamesMain.Text & "*"" "
End If
strSQL = strSQL & "Order By [CE ID];"
' Apply the filter.
Me.cboCENamesMain.RowSource = strSQL
Me.txtRowCount = Me.cboCENamesMain.ListCount
' Drop down the combo list so they can see the results of their filter text.
Me.cboCENamesMain.Dropdown
End If
End Sub