How to use a public function in vba access

[Ezevibe]

I have 9 text boxes in my form that should accept only numbers. I want to warn users anytime text is entered into those text boxes. I also want to warn users that none of the text boxes should be null on editing any value in any of the text boxes with a message that give them the only option to return the boxes to zero.

Now, I want to use a function (either private or public) that does this once. I don't want to code each text boxes separately. Thanks

Thanks

[SioSio]

If you use the class module to make nine textboxes into a control array, you can process them with one event function.

[cactusdata]

Be careful with all these warnings, it's a nuisance to users. Let the computer do the work, that's what they are for.
So, check the key press and accept only number input by, for each textbox, validating the key press:

Private Sub YourTextbox_KeyPress(KeyAscii As Integer)

    ValidateKeyPress KeyAscii

End Sub


Private Sub ValidateKeyPress(ByRef KeyAscii As Integer)

    Const KeyNone   As Integer = 0
    
    Select Case KeyAscii
        Case vbKeyBack
            ' Accept backspace.
        Case Is < vbKey0
            ' Not a number key.
            KeyAscii = KeyNone
        Case Is > vbKey9
            ' Not a number key.
            KeyAscii = KeyNone
    End Select

End Sub

Likewise, accept the Null and replace it when updating the record:

Private Sub Form_BeforeUpdate(Cancel As Integer)

    Me!Textbox1.Value = Nz(Me!Textbox1.Value, 0)
    Me!Textbox2.Value = Nz(Me!Textbox2.Value, 0)
    ' ...
    Me!Textbox9.Value = Nz(Me!Textbox9.Value, 0)
    
End Sub

However, even that can be too much coding if more than a few textboxes (or other controls) are to be handled.
If so, turn to WithEvents. "How", is a story longer than to be told here, but study an example as this: https://github.com/GustavBrock/VBA.ModernTheme.

[SioSio]

Create nine text boxes in the UserForm and code the following:

Option Explicit
Dim myTb() As Class1
Private Sub UserForm_Initialize()
    Dim i As Long
    ReDim myTb(1 To 9)
    For i = 1 To 9
        Set myTb(i) = New Class1
        Set myTb(i).Tb = Me.Controls("TextBox" & CStr(i))
    Next
End Sub

Add a Class1 module and code the following:

Option Explicit
Private WithEvents myTb As MSForms.TextBox
Public Property Set Tb(setTb As MSForms.TextBox)
    Set myTb = setTb
End Property
Public Property Get Tb() As MSForms.TextBox
End Property
Private Sub myTb_MouseUp(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
    MsgBox "Allows you to enter numbers only.", vbOKOnly + vbCritical, "Error"
    myTb.Text = "0"
End Sub
Private Sub myTb_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
    If KeyAscii < Asc("0") Or KeyAscii > Asc("9") Then
       KeyAscii = 0
    End If
End Sub

I'm not sure if the myTb_MouseUp() event fits your needs, so delete it if you don't need it.