疑問 - VB6.0一個公式轉換的問題

[mini]

有個方式可以將 Textbox 限制只能輸入 "數字"

OnlyForTextBoxModule.bas

Option Explicit

Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
    (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
    
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" _
    (ByVal hWnd As Long, ByVal nIndex As Long) As Long

Private Const ES_NUMBER = &H2000
Private Const GWL_STYLE = (-16)

'   只允許輸入數字：
Public Function NumbersOnly(tBox As TextBox)
Dim DefaultStyle As Long

    DefaultStyle = GetWindowLong(tBox.hWnd, GWL_STYLE)
    NumbersOnly = SetWindowLong(tBox.hWnd, GWL_STYLE, DefaultStyle Or ES_NUMBER)

End Function

如何使用，只要在 Private Sub Form_Load()裡加上
NumbersOnly TextBox1
就好了