Wait until user has stopped typing in ComboBox to run macro (VBA) - vba

Question

I'm programming a sort of cross-reference database. An ID is generated based on the document name chosen or created.
The ComboBox I've referred to in the title acts on change (after 3 letters), checks the database for similar entries to what was typed, and displays the drop downof options that match. Once an entry is picked from the match list or a new name created - the appropriate number is generated.
Since the DropDown list is generated after every letter is typed, it takes a while to type what you want. I want to wait a few seconds after the last change to run the macro.
Any Ideas on how I can accomplish this?

Answer 1

An alternative using Application.OnTime again:
In Userform:
Private Sub ComboBox1_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
StartTimer
End Sub
In Module:
Public RunTime As Double
Public Sub StartTimer()
On Error Resume Next
Application.OnTime EarliestTime:=RunTime, Procedure:="YourCode", Schedule:=False
RunTime = Now() + TimeValue("00:00:03")
Application.OnTime RunTime, "YourCode"
End Sub
Public Sub YourCode()
MsgBox "It's working!"
End Sub

Answer 2

This is a bit tricky as VBA doesn't support multi-threading. But we can use the Application.OnTime event to trigger a test in the future to test if the last key event is at least 3 seconds ago.
In a Module insert:
Option Explicit
Public LastKeyEvent As Date
Public Const WaitTimeValue As String = "00:00:03" 'test for key event in 3 seconds
Public Sub TestKeyEvent()
'test if last key event is at least 3 seconds ago.
'If so: run your search or message box
'If not: do nothing
If LastKeyEvent <> 0 And LastKeyEvent + TimeValue(WaitTimeValue) <= Now Then
LastKeyEvent = 0 'Ensure this is only triggered once:
'If we don't do this and multiple keys are pressed within 1 second
'then it would run multiple times.
MsgBox "3 seconds without keypress, we can start search"
'start your search here (instead of message box) …
End If
End Sub
Now you can use for your textbox change event eg TextBox1:
Private Sub TextBox1_Change()
Dim alertTime As Date
LastKeyEvent = Now 'remember when the last key event was
alertTime = LastKeyEvent + TimeValue(WaitTimeValue)
Application.OnTime alertTime, "TestKeyEvent" 'run TestKeyEvent in 3 seconds
End Sub
Note:
This is a workaround that works for 2 or more seconds. But does not for less then 2 seconds.