How to limit TextBox input to a numeric value?

Question

I have code that will create TextBoxes inside a Multipage:

Private Sub CommandButton1_Click()

RowChar = 70
MultiPage1.Pages.Clear

For i = 0 To TextBox1.Value - 1
    MultiPage1.Pages.Add
    MultiPage1.Pages(i).Caption = "Variable" & i + 1

    Call LabelPerPage

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.TextBox.1", "NameBox")
    With txtbx
        .Top = 20
        .Left = 100
    End With

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.TextBox.1", "MinBox")
    With txtbx
        .Top = 50
        .Left = 100
    End With

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.TextBox.1", "LsbBox")
    With txtbx
        .Top = 20
        .Left = 300
    End With

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.TextBox.1", "MaxBox")
    With txtbx
        .Top = 50
        .Left = 300
    End With

    If i = 0 Then
        FormulaString = "= C15"
    Else
        FormulaString = FormulaString & "  " & Chr(RowChar) & "15"
        RowChar = RowChar + 3
    End If
Next i
TextBox2.Value = FormulaString
End Sub

Private Sub LabelPerPage()
    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.Label.1")
    With txtbx
        .Top = 20
        .Left = 50
        .Caption = "NAME:"
    End With

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.Label.1")
    With txtbx
        .Top = 50
        .Left = 50
        .Caption = "MIN:"
    End With

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.Label.1")
    With txtbx
        .Top = 20
        .Left = 250
        .Caption = "LSB:"
    End With

    Set txtbx = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.Label.1")
    With txtbx
        .Top = 50
        .Left = 250
        .Caption = "MAX:"
    End With
End Sub

I tried to create a page and also textbox in it, my problem is I cannot do KeyPress on a TextBox because it will only automatically create because of my code.

Goal:

1.) To do KeyPress were the TextBox cannot input a numberic value or Letter.

2.) I want to compare the two textboxes were textbox1 should be minimum to textbox2

I tried this:

Option 1:

Private Sub MaxBox_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
If (KeyAscii > 46 And KeyAscii < 58) Or KeyAscii = 43 Then
KeyAscii = KeyAscii
Else
KeyAscii = 0
MsgBox "Invalid key pressed, you can enter numbers only"
End If
End Sub

Option 2:

Private Sub OnlyNumbers()
    If TypeName(Me.ActiveControl) = "MaxBox" Then
        With Me.ActiveControl
            If Not IsNumeric(.Value) And .Value <> vbNullString Then
                MsgBox "Sorry, only numbers allowed"
                .Value = vbNullString
            End If
        End With
    End If
End Sub

Answer 1

Why not lose the keyPress altogether, since the only thing you're trying to achieve is Numeric Input only? You can just do something like this in your userform code:

Option Explicit
'Variable to capture Change event from your textbox:
Private WithEvents maxbox As MSForms.TextBox

'The creation of the thing; I just created a multipage control to reuse your lines.
Private Sub UserForm_Initialize()
    Dim txtbox as MSForms.TextBox
    Dim i As Integer
    i = 0
    Set txtbox = UserForm1.MultiPage1.Pages(i).Controls.Add("Forms.TextBox.1", "MaxBox")
    With txtbox 
        .Top = 50
        .Left = 50
    End With
    Set maxbox = txtbox
End Sub

'Capture change of maxbox:
Private Sub maxbox_Change()
    'In case somebody entered something non-numeric:   
    If IsNumeric(maxbox.Text) = False Then
        'Remove the input character
        maxbox.Text = Left(maxbox.Text, Len(maxbox.Text) - 1)
        'And alert the user
        MsgBox "numeric only!"
    End If
End Sub

If you need multiple, you can also just create a custom class where you capture the event, and add a collection of that class to the Userform. For doing that, you can have a look at the answers on this question

Edit: For the second half (validate against the Minbox) you can use the same event: Just add another if statement to ensure the numeric value is > CInt(minbox.text) (or another numeric type).

Edit 2: You might want to add error handling for the Left(maxbox.Text, Len(maxbox.Text) - 1) bit in case the Length of the string is 0 (i.e. when somebody pressed backspace / delete to trigger the change event).