Message in Chinese (Traditional) (中文（繁體）)
在驗證執行前，不可以呼叫 Page.IsValid，應該在 CausesValidation=True 的控制項的事件處理常式中查詢，或是在呼叫 Page.Validate 之後才進行查詢。
Unlocalized message
Page.IsValid cannot be called before validation has taken place. It should be queried in the event handler for a control that has CausesValidation=True and initiated the postback, or after a call to Page.Validate.
Search by Google