Login | Register   
RSS Feed
Download our iPhone app
Browse DevX
Sign up for e-mail newsletters from DevX

By submitting your information, you agree that devx.com may send you DevX offers via email, phone and text message, as well as email offers about other products and services that DevX believes may be of interest to you. DevX will process your information in accordance with the Quinstreet Privacy Policy.

Tip of the Day
Language: VB7
Expertise: Intermediate
Oct 6, 2003



Building the Right Environment to Support AI, Machine Learning and Deep Learning

Enable a key-skipping mechanism for a TextBox

' Enable the key-skipping mechanism for the input TextBox and for the input 
' chars
' Example: don't process the 'A', 'b' and '0' chars
'   EnableTextBoxCharSkip(TextBox1, "A"c, "b"c, "0"c)

Sub EnableTextBoxCharSkip(ByVal tb As TextBox, ByVal ParamArray keysToSkip() As _
    ' save the array of keys textbox's Tag property
    tb.Tag = keysToSkip
    ' attach the txtbox's KeyPress event to the GenTextBox_KeyPress event 
    ' handler
    AddHandler tb.KeyPress, AddressOf GenTextBox_KeyPress
End Sub

' Disable the key-skipping mechanism for the input textbox
' Example: DisableTextBoxCharSkip(TextBox1)

Sub DisableTextBoxCharSkip(ByVal tb As TextBox)
    ' detach the textbox's KeyPress event from the GenTextBox_KeyPress event 
    ' handler
    RemoveHandler tb.KeyPress, AddressOf GenTextBox_KeyPress
    tb.Tag = Nothing
End Sub

' Handle the textbox's KeyPress event to skip the keys of the array stored in 
' the textbox's Tag property
Private Sub GenTextBox_KeyPress(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.KeyPressEventArgs)
    ' cast the generic Object sender to a TextBox
    Dim tb As TextBox = DirectCast(sender, TextBox)
    ' cast the textbox's Tag to an array of Char, that contains the chars to 
    ' skip
    Dim keysToSkip() As Char = DirectCast(tb.Tag, Char())
    ' if the pressed key is found in the array of "bad" keys,
    '  overrides its default processing with "do nothing"
    If Array.IndexOf(keysToSkip, e.KeyChar) > -1 Then e.Handled = True
End Sub
Marco Bellinaso
Comment and Contribute






(Maximum characters: 1200). You have 1200 characters left.



Thanks for your registration, follow us on our social networks to keep up-to-date