Regenerating the Designer.cs File (重新產生 designer.cs)

1. Delete the current designer.cs file
   (刪除 .designer.cs 檔)
2. Right click on the .aspx file and choose Convert to Web Application
   (在欲重新產生的程式上按滑鼠右鍵，點選 "轉換成網站應用程式)