發生異常時，清理並關閉interop excel com對象。 Winforms vb.net

Question

如何正確清理excel com對象。掛在任務管理器運行Excel過程時，與對象

工作時，如果沒有錯誤，則退出程序後有被拋出異常沒有EXCEL.EXE過程在任務管理器

我的示例代碼留下。如果你註釋掉錯誤行並關閉應用程序，那麼一切都很好。如何處理這種錯誤情況下的清理？

Imports Microsoft.Office.Interop 

Public Class Form1 
    Private xlApp As Excel.Application 
    Private xlWorkBook As Excel.Workbook 
    Private misValue As Object 
    Property xlWorkSheet As Excel.Worksheet 

    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 
     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 = xlWorkBook.Sheets("sheet1") 
      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 & Name & "Output.xls" 
      xlApp.DisplayAlerts = False 
      xlWorkBook.CheckCompatibility = False 
      xlWorkBook.DoNotPromptForConvert = True 
      xlWorkBook.SaveAs(Dir, Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, _ 
           Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue) 

     Catch ex As Exception 
      Dim exMsg = ex.Message 
     Finally 
      ''TIME TO CLEAN EXCEL STUFF 
      Cleanup() 
     End Try 
    End Sub 

    Private Sub Cleanup() 
     ReleaseObject(xlWorkSheet) 
     ReleaseObject(xlWorkBook) 
     xlApp.Quit() 
     ReleaseObject(xlApp) 
    End Sub 

    Private Sub ReleaseObject(ByRef obj As Object) 
     Try 
      If Not IsNothing(obj) And System.Runtime.InteropServices.Marshal.IsComObject(obj) Then 
       System.Runtime.InteropServices.Marshal.ReleaseComObject(obj) 
       obj = Nothing 
      End If 
     Catch ex As Exception 
      obj = Nothing 
     Finally 
      GC.Collect() 
     End Try 
    End Sub 

End Class 

Answer 1

想通了。在釋放對象之前需要調用xlWorkBook.close和xlApplication.Quit。這裏是更新的功能，清除

Private Sub Cleanup() 
    xlWorkBook.Close(False) 
    xlApp.Quit() 
    ReleaseObject(xlWorkSheet) 
    ReleaseObject(xlWorkBook) 
    ReleaseObject(xlApp) 
End Sub