numerical textbox

in something like...

if txtBox.text = "" then
msgbox "enter something in the textbox please"

how would i change that if I only wanted numerical data inputted?

thanks

This will also eliminate Cut n Paste problems.

And....

Using the Validate Event prevents the TextBox loosing focus
before the validation is conducted (which would result in invalid
data remaining in the TextBox.

However, whilst a user can temporaraly enter invalid data, when
they move to another control they are alerted, and sent
back to the TextBox until a valid entry is made.

VB Code:

Private Sub Text1_Validate(Cancel As Boolean)
    For i = 1 To Len(Text1.Text)
        If Not IsNumeric(Mid(Text1.Text, i, 1)) Then
            MsgBox "Invalid Charater, Numbers Only please"
            Text1.SelStart = i - 1
            Text1.SelLength = 1
            Text1.SetFocus
            Cancel = True
            Exit Sub
        End If
    Next
End Sub

Here is a control that I wrote called NumberBox. It is essentially a textbox that limits input to numbers. It also has the following new properties.

CanBeNegative
CanHaveDecimals
MaxDecimals

thanks guys, just what i was lookin for :)