无法从Excel删除工作表，甚至使用VB.NET没有错误？

Question

I have:

Public Class ExcelProcess
    Private App As New Excel.Application
    Private Books As Excel.Workbooks = App.Workbooks
    Private WB As Excel.Workbook

Public Sub deleteSheets()
    Dim sheet As Excel.Worksheet = getSheetToDelete()
    sheet.Activate()
    sheet.Delete()
    WB.Save()
    WB.Close()
End Sub

Private Function getSheetToDelete() As Excel.Worksheet
     Try
        WB = Books.Open("file.xlsx")
    Catch ex As Exception
        InputOutput.print(ex.Message)
        End
    End Try
    Return WB.Sheets(1)
End Function

End Class

I ran the above code, and it ran successfully with absolutely no errors or exceptions!

But the sheet didn't get deleted!

< UPDATE >

I have also tried:

sheet.Select()
sheet.Delete()

' Now, this gave me an exception:
Unhandled Exception: System.Runtime.InteropServices.COMException: Exception from HRESULT: 0x800A03EC
at Microsoft.Office.Interop.Excel._Worksheet.Select(Object Replace)
at DealerCapReport.ExcelProcess.deleteSheets()
at DealerCapReport.MainModule.Main()

< Another UPDATE >

I tried to check sheet.Delete() boolean for success of failure:

If sheet.Delete() Then        ' Error: Expression does not produce a value.
    Console.WriteLine("Can-not Delete")
End If

It says Error: Expression does not produce a value. in sheet.Delete().

The strange thing is that the Microsoft API reference says that it would produce a Boolean, but it doesn't as it is a Sub and not a function.

How and what is happening?

Am I doing something wrong?

Please help me fix this!

Answer 1

The following code works for me ( EDITED to include some error checking ):

Public Class ExcelProcess
    Private xlApp As Excel.Application
    Private xlBook As Excel.Workbook
    Private xlSheet As Excel.Worksheet

    Public Sub New(ByVal file As String)
        xlApp = New Excel.Application
        'xlApp.Visible = True 'for debugging
        xlApp.DisplayAlerts = False 'prevent user dialogs
        xlBook = xlApp.Workbooks.Open(file)
    End Sub

    Public Sub Quit()
        If Not IsNothing(xlBook) Then
            xlBook.Save()
            xlBook.Close()
        End If
        If Not IsNothing(xlApp) Then xlApp.Quit()
    End Sub

    Public Sub deleteSheet(ByVal Index As Integer)
        If Index > xlBook.Worksheets.Count Then
            Throw New Exception("You cannot delete a worksheet that does not exist")
            Exit Sub
        End If
        If xlBook.Worksheets.Count = 1 Then
            Throw New Exception("You cannnot delete the only worksheet in a workbook")
            Exit Sub
        End If
        xlSheet = CType(xlBook.Worksheets(Index), Excel.Worksheet)
        xlSheet.Activate()
        xlSheet.Delete()
    End Sub

End Class

Answer 2

I would suggest that you need to save your workbook after you do the delete (using SaveAs ). Otherwise it will just delete the in-memory worksheet and when your Excel object goes out of scope it will just close the workbook without saving the changes.

Books.SaveAs(...)