Down below is code for creating a control, NumericTextbox
Public Class NumericTextbox
    Inherits System.Windows.Forms.TextBox
    Private Sub NumericTextbox_KeyPress(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles MyBase.KeyPress
        Dim KeyAscii As Integer
        KeyAscii = Asc(e.KeyChar)
        Select Case KeyAscii
            Case 48 To 57, 8, 13
            Case 45 'minus tecken
                If InStr(Me.Text, "-") <> 0 Then
                    KeyAscii = 0
                End If
            Case 46 'punkt
                If InStr(Me.Text, ".") <> 0 Then
                    KeyAscii = 0
                End If
            Case Else
                KeyAscii = 0
        End Select
        If KeyAscii = 0 Then
            e.Handled = True
        Else
            e.Handled = False
        End If
    End Sub
End Class

which only allow users to enter digits, not characters. The code is from the book Professional VB.NET.

But if I use this control on a form and uses the control NumericTextbox:s event KeyPress like this

Private Sub NumericTextbox1_KeyPress(ByVal sender As Object, ByVal e As
System.Windows.Forms.KeyPressEventArgs) Handles NumericTextbox1.KeyPress
    Me.NumericTextbox1.Text = e.KeyChar
End Sub

you can put characters in the textbox. The KeyPress event shouldn't be
available in the left-hand drop-down box for the NumericTextbox1, since we have used the KeyPress event for our control to make it just allow digits, not characters. Is there a way to remove the KeyPress event from the left-hand drop-down box for the NumericTextbox, so the users of the control NumericTextbox can't use the KeyPress event or is there another way to make the KeyPress event unavailable for users of the NumricTextbox???

Please Help

Fia

What is “the left-hand drop-down box for the NumericTextbox1” and “the left-hand drop-down box for the NumericTextbox”?

It would be interesting to know the order in which these KeyPress events are handled. I suspect that both the textbox contained in the control that you have built, and the instance of that control in your program both get a shot at the key press (though I would have thought that the e.Handled = True would have warded off the instance’s opportunity to handle it).

Have you tried

The left-hand drop-down box for the NumericTextbox or the NumericTextbox1 is the same. When I tried to use e.KeyChar = 0, I got an error and it said that property KeyChar is ReadOnly.

Fia

What do you mean by “The left-hand drop-down box for the NumericTextbox”?
Textboxes do not have drop-down anythings!
Have you added a special button beside the textbox to show a list box?
Are you using combo boxes, but mistakenly calling them textboxes?
Plus, drop-down buttons are on the right.

I am asking for clarification on what you mean by “the left-hand drop-down box” for [u]whatever</u>. What is a left-hand drop-down—as a [u]class</u> of thing?