Custom control mybase.OnTextChanged not firing - vb.net

Question

I have a custom text box control which validates input (striped out unwanted chars). This works fine apart from when I also want to do further processing on an implementation of the control.
Example I have 3 "specialTextbox"s on a form. sText1, sText2 and sText3. sText1 & sText2 work as as intended. However, I need to make changes on the forum when the value of sText3 is changed, so I have a handler in the form to handle the ctext changed event:
Private Sub sText3(sender As Object, e As EventArgs) Handles sText3.TextChanged
'do some stuff here
End Sub
However this routine appears to override the OnTextChanged method of the custom text box. I have tried includeing a call to MyBase.OnTextChanged, but this still doesn't cascade up and no matter what I do I can't seem to get the text box to do its validation duties.
Must be something really simple, but I'm stumped!
Here is a class which overrides textbox
Public Class restrictedTextBox
Inherits Windows.Forms.TextBox
Protected validChars As List(Of Char)
Public Sub New(ByVal _validChars As List(Of Char))
MyBase.New()
validChars = _validChars
End Sub
Public Sub setValidChars(ByVal chrz As List(Of Char))
validChars = chrz
End Sub
Protected Overrides Sub OnTextChanged(e As System.EventArgs)
MyBase.OnTextChanged(e)
Dim newValue As String = ""
For Each c As Char In Me.Text.ToCharArray
Dim valid As Boolean = False
For Each c2 As Char In validChars
If c = c2 Then valid = True
Next
If valid Then newValue &= c.ToString
Next
Me.Text = newValue
End Sub
End Class
Here is a form which has a a custom textbox
Public Class frmNewForm
Private Sub btnOK_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnOK.Click
MessageBox.Show("the text from the restricted text is: " & txtRestricted.Text)
End Sub
End Class
Here is a form with a custom text box, which implements the TextChanged event
Public Class frmNewForm2
Private Sub btnOK_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnOK.Click
MessageBox.Show("the text from the restricted text is: " & txtRestricted.Text)
End If
Private Sub txtRestricted_TextChanged(sender As Object, e As EventArgs) Handles txtRestricted.TextChanged
'now that I have implemented this method, the restrictedTextBox.OnTextChanged() doesn't fire - even if I call MyBase.OnTextChanged(e)
'just to be completely clear. the line of code below DOES get executed. But the code in restrictedTextBox.vb does NOT
lblAwesomeLabel.Text=txtRestricted.Text
End Sub
End Class

Answer 1

It fires, but probably not the way you are implementing it.
Your sample code does not have an empty constructor for the textbox, which means you are most likely not using the designer when you are adding the textbox to the form.
But your form shows it was created by the designer:
Private Sub txtRestricted_TextChanged(sender As Object, e As EventArgs) _
Handles txtRestricted.TextChanged
End Sub
That's not possible with your posted code. If you are creating "new" controls programmatically, then you need to wire up the events programmatically, too.
Drop the handler and just leave the stub:
Private Sub txtRestricted_TextChanged(sender As Object, e As EventArgs)
'yada-yada-yada
End Sub
then when you create a new textbox, wire it up:
txtRestricted = new restrictedTextBox(myCharsList)
AddHandler txtRestricted.TextChanged, AddressOf txtRestricted_TextChanged
Me.Controls.Add(txtRestricted)