发生异常时清理并关闭Interop Excel Com对象.winforms vb.net

Question

如何正确清理excel com对象。当使用对象

时，在任务管理器中悬挂Excel进程在任务管理器中运行

如果没有错误，则退出应用程序后没有excel.exe进程在taskmanager

中留下

我的示例代码。如果您评论错误行并关闭应用程序，则一切都很好。如何处理诸如此类错误的错误案件中的清理？

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

弄清楚了。xlworkbook.close和xlapplication.quit在释放对象之前需要调用。这是更新的清理功能

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