另外，

Sub UserForm1_starttrade_Click()
    if marketdata.IsExistStock(userform1_codebox.text,userform1_marketbox.text)=0 then 
       application.MsgOut "品種或市場錯誤"
       application.MsgOut userform1_codebox.text & "  " & userform1_marketbox.text
       exit sub
    end if

end sub

marketdata.isexiststock的用法不是這樣嗎？這樣子總是提示 品種或市場錯誤