阅读以下代码,完整陈述其功能: Private Sub Workbook_BeforeClose(Cancel As Boolean) Dim ws As Worksheet For Each ws In ThisWorkbook.Worksheets If ws.Visible = False Then Cancel = True MsgBox "存在隐藏工作表,不允许关闭" End If Next ws If ThisWorkbook.Saved = False Then ThisWorkbook.Save Cancel = False End If End Sub