爲什麼在程序運行時Excel進程關閉

Question

問題：爲什麼在程序運行時Excel進程不關閉？請不要跳槍，並標記重複。如果您可以在代碼中顯示所需的更改，我真的很感激它。 當我關閉應用程序時，Excel進程關閉很好。我在最近幾天研究了這個問題，閱讀了幾篇SO帖子，並嘗試了幾件事情，但除了調用process.kill外，沒有什麼可行的，我寧願儘可能避免。

Imports Microsoft.Office.Interop 
Imports System.Runtime.InteropServices 

Public Class Form1 

    Public Sub New() 

     ' This call is required by the designer. 
     InitializeComponent() 

     ' Add any initialization after the InitializeComponent() call. 
    End Sub 

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
     Dim xlApp As Excel.Application 
     Dim xlWorkBook As Excel.Workbook 
     Dim misValue As Object 
     Dim xlWorkSheet As Excel.Worksheet 

     Try 
      ''EXCEL CREATION/INITAILIAZATION 
      misValue = System.Reflection.Missing.Value 
      xlApp = New Microsoft.Office.Interop.Excel.Application() 
      If xlApp Is Nothing Then 
       MessageBox.Show("Excel is not properly installed!!") 
       xlApp = Nothing 
      End If 
      xlWorkBook = xlApp.Workbooks.Add(misValue) 


      ''WRITE TO WORKSHEET 
      xlWorkSheet = TryCast(xlWorkBook.Sheets("sheet1"), Excel.Worksheet) 
      xlWorkSheet.Cells(1, 1) = "THIS" 
      xlWorkSheet.Cells(1, 2) = "IS" 
      xlWorkSheet.Cells(1, 3) = "A" 
      xlWorkSheet.Cells(1, 4) = "TEST" 

      ''FORCEFULLY CAUSING ERROR, NOW THE EXCEL PROCESS HANGING IN TASK MANAGER 
      ''xlWorkSheet.Cells(1, -1) = "ERROR LINE" 

      ''SAVE WORKSHEET 
      Dim Name = DateTime.Now.ToString("s").Replace(":", "_") 
      Dim Dir = AppDomain.CurrentDomain.BaseDirectory & "Output\" & Name & "Output.xls" 
      xlApp.DisplayAlerts = False 
      xlWorkBook.CheckCompatibility = False 
      xlWorkBook.DoNotPromptForConvert = True 
      xlWorkBook.SaveAs(Dir, Excel.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, _ 
           Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing) 
      xlWorkBook.Close(False) 
      xlApp.Quit() 

      misValue = Nothing 

      If Not IsNothing(xlWorkSheet) And System.Runtime.InteropServices.Marshal.IsComObject(xlWorkSheet) Then 
       System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkSheet) 
       xlWorkSheet = Nothing 
      End If 

      If Not IsNothing(xlWorkBook) And System.Runtime.InteropServices.Marshal.IsComObject(xlWorkBook) Then 
       System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkBook) 
       xlWorkBook = Nothing 
      End If 

      If Not IsNothing(xlApp) And System.Runtime.InteropServices.Marshal.IsComObject(xlApp) Then 
       System.Runtime.InteropServices.Marshal.FinalReleaseComObject(xlApp) 
       xlApp = Nothing 
      End If 

      GC.Collect() 
      GC.WaitForPendingFinalizers() 

     Catch ex As Exception 
      Dim exMsg = ex.Message 
     End Try 
    End Sub 

End Class 

Answer 1

您的問題是.net中的雙點引用。在這裏閱讀：https://msdn.microsoft.com/en-us/library/8bwh56xe(v=vs.110).aspx

所以一旦你解構

xlWorkBook = xlApp.Workbooks.Add(misValue) 

爲

xlWorkBooks = xlApp.Workbooks 
xlWorkBook = xlWorkBooks.Add(misValue) 

然後鬆開，你都好。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    Call doSomeWork() 
    GC.Collect() 
End Sub 

Private Sub doSomeWork() 
    Dim xlApp As Excel.Application 
    Dim xlWorkBook As Excel.Workbook 
    Dim xlWorkBooks As Excel.Workbooks '// Added new variable to avoid double dot. 
    Dim misValue As Object 
    Dim xlWorkSheet As Excel.Worksheet 

    Try 
     ''EXCEL CREATION/INITAILIAZATION 
     misValue = System.Reflection.Missing.Value 
     xlApp = New Microsoft.Office.Interop.Excel.Application() 
     If xlApp Is Nothing Then 
      MessageBox.Show("Excel is not properly installed!!") 
      xlApp = Nothing 
     End If 
     xlWorkBooks = xlApp.Workbooks 
     xlWorkBook = xlWorkBooks.Add(misValue) 


     ''WRITE TO WORKSHEET 
     xlWorkSheet = xlWorkBook.Sheets(1) 

     'xlWorkSheet = TryCast(sheets("sheet1"), Excel.Worksheet) 
     xlWorkSheet.Cells(1, 1) = "THIS" 
     xlWorkSheet.Cells(1, 2) = "IS" 
     xlWorkSheet.Cells(1, 3) = "A" 
     xlWorkSheet.Cells(1, 4) = "TEST" 

     ''FORCEFULLY CAUSING ERROR, NOW THE EXCEL PROCESS HANGING IN TASK MANAGER 
     ''xlWorkSheet.Cells(1, -1) = "ERROR LINE" 

     ''SAVE WORKSHEET 
     Dim Name = DateTime.Now.ToString("s").Replace(":", "_") 
     Dim Dir = AppDomain.CurrentDomain.BaseDirectory & "Output\" & Name & "Output.xls" 
     xlApp.DisplayAlerts = False 
     xlWorkBook.CheckCompatibility = False 
     xlWorkBook.DoNotPromptForConvert = True 
     xlWorkBook.SaveAs("C:\temp\a.xls", Excel.XlFileFormat.xlWorkbookNormal, Type.Missing, Type.Missing, Type.Missing, Type.Missing, _ 
          Excel.XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing) 
     xlWorkBook.Close(False) 
     xlApp.Quit() 

     misValue = Nothing 

    Catch ex As Exception 
    End Try 
End Sub