Need help with setting up textchanged on all textboxes...

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I have a win form with 43 textboxes and I am wanting to enable a button if any of the boxes has been changed. the following code is what I have. This is in the Form_Load routine. I added the message box to see if it is working but it is not. What am I missing or doing wrong.

What I have tried:

'Setup TextChanged flag for all textboxes
        For Each Control As Control In Me.Controls
            If Control.GetType = GetType(TextBox) Then
                Dim TextBox As TextBox = DirectCast(Control, TextBox)
                AddHandler TextBox.TextChanged, AddressOf TextBoxTextChanged_Handler
                MsgBox(TextBox.Name & " was changed.") 'Added this message box to see if the sub is working 
            End If
        Next

I have the following but it doesn't fire:

' TextChangedEventHandler delegate method.
    Sub TextBoxTextChanged_Handler(ByVal sender As Object, ByVal e As EventArgs)
        Dim TextBox As TextBox = DirectCast(sender, TextBox)
        MsgBox(TextBox.Name & " was changed.")
    End Sub

Posted 5-Feb-20 14:19pm

bgcwaterman

Updated 5-Feb-20 20:15pm

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Ralf Meier 6-Feb-20 4:51am

I'm not complete sure but I suppose that at the end of Form_Load the Controls of the Form are instances - not before. I would try it with another event from the Form.
Another point : For me it's allways weird to give a variable the same Name as the Type to which it's refering (For each control as Control ... - better : for each c as control)

Richard Deeming 6-Feb-20 9:25am

For Windows Forms, the controls will exist as soon as the designer-generated InitializeComponent method returns. That's usually called from the constructor, so the controls will exist long before the Load event fires. :)

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phil.o · Accepted Answer · 2020-02-05T20:15:00

Solution 1

It is possible that textboxes are not directly in form's Controls property; they could be contained by another control (GroupBox, etc...).

You could put a breakpoint on the foreach line and see which controls you grab.

Or you could statically define the handler in IDE by selecting all textboxes and affecting them the handler.

Posted 5-Feb-20 20:15pm

phil.o

Comments

bgcwaterman 6-Feb-20 9:57am

The textboxes are in group boxes. I will need to figure out how to do this for text boxes in group boxes.

phil.o 6-Feb-20 10:06am

You could do

For Each ctl As Control In Me.Controls
   If ctl.GetType = GetType(GroupBox) Then
      For Each tb As Control in ctl.Controls
         '' ...

but imho the solution to statically assign the handler from IDE is much simpler (unless you are building the controls at runtime).

bgcwaterman 6-Feb-20 10:08am

How would you do the IDE method? thanks

phil.o 6-Feb-20 10:12am

- Go to the design view of the form.
- Select all text boxes.
- In the 'Properties' window (usually on the right), there is an 'Events' button (which allows to display events for selected control(s) instead of properties).
- Go to the TextChanged event, and select the handler.
And don't forget to delete the part where you tried to do it programmatically, which won't be needed anymore.

bgcwaterman 6-Feb-20 10:21am

I don't have a "Events" button in the properties window after I select the textboxes.

bgcwaterman 6-Feb-20 10:24am

I found the "events" button... Sorry for my inexperience. Thanks.

phil.o 6-Feb-20 10:31am

No problem, everyone has been there at some point :)
You're welcome!

bgcwaterman 6-Feb-20 10:42am

Got it to work. I just need to setup what I want to do with the handler... The strange thing is I have to go to each control to set the handler because if I select multiple controls the "TextChanged" event doesn't shop up.... thanks...