How do I get the 'Value' property from a MSAccess Form textBox while it's being edited?

Question

How do I capture the value being typed into a MS Access Form's textBox control as it's being edited? I'd like to show results of a search (in a listbox) that's updated with each new character added to the textBox used for the search? The query is in place, the events are in place, the only thing that's missing is where is the typed value stored, because it's not in the control's .Value property during "typing" events.

Answer 1

The key to achieving this is using the OnChange event of the text box, which fires for every keystroke which changes the content of the text box.

As such, you can easily change the content of the list box by referencing the Text property of the text box within the event handler for the OnChange event.

Here is a very basic demonstration searching a list of animal names:

Answer 2

Notice, many of my attempts to read state below (and in previous edits) are garbage. I have this query building function that is executed at a variety of times (not listed in the question, mia culpa). I'm now passing in state as a parameter for said query function rather than trying to read it actively. I'm leaving this up as a caution to anyone who goes down a similar path. I apologize if I've steered anyone wrong thus far.

The 'Value' property of a textBox isn't updated on change or keyup events, as one might expect. If you wish to capture the contents typed into a textBox as they're being typed, you'll need to look for the 'Text' property, as in:

Me.txtSearchBox.Text

Unfortunately, this property isn't accessible unless the textBox is active, so if you're reading .Text while interacting with a different control you'll want to test that the textBox is active, which it won't be, and fail over to checking 'Value' instead, as in:

' assuming you've already dim'd the strSearchBox as String here...
If Screen.ActiveControl.Name = txtSearchBox.Name Then
    ' the control is active, so for the moment, Text is accessible
    strSearchBox = Trim(txtSearchBox.Text & vbNullString)
Else
    ' textBox failover:
    ' Value is always accessible
    strSearchBox = Trim(txtSearchBox.Value & vbNullString)
End If
' strSearchBox now has the contents of txtSearchBox, one way or the other

Yes, I'm a compulsive Trim()er. Yes, I cast to string by appending "" (corrected to vbNullString per @ComputerVersteher -- many thanks). Please do shout at me if that's horrible. The point is, .Value can be null on form load, and assigning null value to a string variable is breaking.

Unfortunately, if you're going to run this code while in going in and out of debug or loading the form Screen.ActiveControl.Name isn't going to be callable. You may resolve this by testing that the form in question is actually loaded, like so:

If not CurrentProject.AllForms(Me.Name).IsLoaded Then
    ' activeform failover:
    ' Value is always accessible
    strSearchBox = Trim(txtSearchBox.Value & vbNullString)
Else
    ' there's an Form loaded, so there is an ActiveControl Name to test
    If Screen.ActiveControl.Name = txtSearchBox.Name Then
        ' the control is active, so for the moment, Text is accessible
        strSearchBox = Trim(txtSearchBox.Text & vbNullString)
    Else
        ' textBox failover:
        ' Value is always accessible
        strSearchBox = Trim(txtSearchBox.Value & vbNullString)
    End If
End If

I hope this saves a few folks out there a little time. Maybe it will save you time if you read it and don't follow my advice. Check out the edits to see other bad ideas about reading state of a VB form and bad assumptions about control names being unique, etc...