check if number

I have the tipical "check if valid" in a TextFiled

How can I Check if a String is a number... (int or double)


If isNotNumber(MyString) Then
ThisTextField.SetFocus()

This will check that any text is a number:

VB Code:

If Not isNumeric(MyString) Then
  ThisTextField.SetFocus()
End If

and this will do the same, plus make sure that something has been entered (the above will allow empty text)

VB Code:

If (Not isNumeric(MyString)) Or (MyString = "") Then
  ThisTextField.SetFocus()
End If