ms access出货量與庫存之間的驗證問題

我有一个input box输入出货数量
但我的代码有一些问题
如果数量>库存数量
输入框会一直循环

问题是

库存水平是200

我进了50，但input box仍然循环

我不知道我的代码做错了什么

代码是 If (Myquantity <> "") Then Q = ValidateQ(Myquantity)

            Loop While (Q = False) Or (Myquantity = "") Or (Myquantity = "0") Or (Myquantity > Me.Stock_level)

下面是我整个input box的代码

  Do
   Myquantity = InputBox("Please Specify the Quantity of ProductID." _
                 & Me.ProductID & vbCr & "")
                 
   If (Myquantity <> "") Then Q = ValidateQ(Myquantity)
            Loop While (Q = False) Or (Myquantity = "") Or (Myquantity = "0") Or (Myquantity > Me.Stock_level)

   Forms![F_Orders].[F_Order_line_subform].SetFocus
  DoCmd.GoToRecord , , acLast
   Me.Parent.F_Order_line_subform.Form!Quantity = Myquantity
   MsgBox "The order of ProductID." _
                                & Me.ProductID & vbCr & "successfully added to order"

Function ValidateQ(Myquantity As String) As Boolean
    Dim strLength As Integer
    Dim I As Integer
    
    Myquantity = Trim(Myquantity)
    strLength = Len(Myquantity)
 For I = 1 To strLength

If Myquantity = "0" Then
ValidateQ = False
 msb = MsgBox("Invalid values, this values is not allow to enter , try again", vbCritical, "Error")
 Else
  ValidateQ = True
 
       End If
        
    Next I
    If (Myquantity <> "") Then
    If IsNumeric(Myquantity) Then
    ValidateQ = True
    Else
        ValidateQ = False
        msb = MsgBox("invalid values,PLease enter a Numeric values ", vbCritical, "Error")
    
        
  End If
  End If
End Function