I am trying to set up a form to accept a telephone number, but i am unsure of how to validate it so it will only take numeric values with 11 digits.
So far i have it working to ensure that there is something in the textbox
'Validate data for Telephone Number
If txtTelephoneNumber.Text = "" Then
txtTelephoneNumber.Focus()
MessageBox.Show("You must enter a Telephone Number.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Information)
I'll imply you are using Windows Forms.
Write this as your TextBox's Key Pressed event.
Private Sub myTxtBox_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles myTxtBox.KeyPress
If txtTelephoneNumber.Text.Length > 11 Then
e.Handled= True
return
End If
If Asc(e.KeyChar) <> 8 Then
If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then
e.Handled = True
End If
End If
End Sub
This should (did not have time to test it) keep the user from inputing anything that is not a number. It should prevent him from inputting more than 11 numbers too.
Put this in your KeyPress event of the TextBox
'makes sure that only numbers and the backspace are allowed in the fields.
Dim allowedChars As String = "0123456789" & vbBack
'get a reference to the text box that fired this event
Dim tText As TextBox
tText = CType(sender, TextBox)
If allowedChars.IndexOf(e.KeyChar) = -1 Then
' Invalid Character
e.Handled = True
End If
if tText.Text.Length >= 11 then
e.Handled = True
End If
In your textbox keydown event. Use the following:
If Not IsNumeric(Chr(e.KeyCode)) Then
e.SuppressKeyPress = True
End If
If you want allow other characters you would do it like so:
If Not IsNumeric(Chr(e.KeyCode)) And Not e.KeyCode = 8 And Not e.KeyCode = 46 Then
e.SuppressKeyPress = True
End If
'(8 = backspace key and 46 = Delete key)
You can try
If txtTelephoneNumber.Text = "" Or Not IsNumeric(txtTelephoneNumber.Text) Or txtTelephoneNumber.Text.Length <> 11 Then
txtTelephoneNumber.Focus()
MessageBox.Show("You must enter a Telephone Number.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Information)
I use this for the keypress event
If e.KeyChar < CStr(0) Or e.KeyChar > CStr(9) Then e.Handled = True
Actually that looks different to what i remember using, but it works. Though you'll need to allow backspace too.
Or i guess even shorter would be
If Not IsNumeric(e.KeyChar) Then e.Handled = True
also keypress event.
You can set the maximum length of a textbox using MaxLength
set max length to 12 put this in keypress of text1 and it will format it with dashes and only numbers
If Len(Text1.Text) = 3 Or Len(Text1.Text) = 7 Then
Text1.Text = Text1.Text & "-"
Text1.SelStart = Len(Text1.Text)
End If
If KeyAscii <> 127 And KeyAscii <> 8 And KeyAscii <> 13 Then
If IsNumeric(Chr(KeyAscii)) = False Then
KeyAscii = 0
End If
ElseIf KeyAscii = 8 Then
If Right(Text1.Text, 1) = "-" Then
Text1.Text = Left(Text1.Text, Len(Text1.Text) - 1)
Text1.SelStart = Len(Text1.Text)
End If
End If
if you only want numeric text box use the following in the keypress
If KeyAscii <> 127 And KeyAscii <> 8 And KeyAscii <> 13 Then
If IsNumeric(Chr(KeyAscii)) = False Then
KeyAscii = 0
End If
End If
You can use the lostfocus event and in this event you can put something like this:
if not isnumeric(textbox1.text) then
textbox1.gotfocus 'this part is to validate only numbers in the texbox and not let
' him go from the texbox
endif
and you should define the maxlength for the textbox in just 11 characters
