[英]Reading excel files in vb.net leaves excel process hanging
以下代碼工作正常,但似乎讓excel.exe的實例在后台運行。 我如何正確地關閉這個子?
Private Sub ReadExcel(ByVal childform As Fone_Builder_Delux.frmData, ByVal FileName As String)
' In progress
childform.sampleloaded = False
Dim xlApp As Excel.Application
Dim xlWorkBook As Excel.Workbook
Dim xlWorkSheet As Excel.Worksheet
xlApp = New Excel.ApplicationClass
xlWorkBook = xlApp.Workbooks.Open(FileName)
xlWorkSheet = xlWorkBook.Worksheets(1)
Dim columnrange = xlWorkSheet.Columns
Dim therange = xlWorkSheet.UsedRange
childform.datagridHeaders.Columns.Add("", "") ' Super imporant to add a blank column, could improve this
For cCnt = 1 To therange.Columns.Count
Dim Obj = CType(therange.Cells(1, cCnt), Excel.Range)
childform.datagridSample.Columns.Add(Obj.Value, Obj.Value)
childform.datagridHeaders.Columns.Add(Obj.Value, Obj.Value)
Next
For rCnt = 2 To therange.Rows.Count
Dim rowArray(therange.Columns.Count) As String
For cCnt = 1 To therange.Columns.Count
Dim Obj = CType(therange.Cells(rCnt, cCnt), Excel.Range)
Dim celltext As String
celltext = Obj.Value.ToString
rowArray((cCnt - 1)) = celltext
'MsgBox(Obj.Value)
Next
childform.datagridSample.Rows.Add(rowArray)
Next
AdjustHeaders(childform)
childform.sampleloaded = True
End Sub
簡短回答:適當地關閉每個項目,然后在它們上調用FinalReleaseComObject 。
GC.Collect()
GC.WaitForPendingFinalizers()
If xlWorkSheet Is Nothing Then Marshal.FinalReleaseComObject(xlWorkSheet)
If xlWorkBook Is Nothing Then
xlWorkBook.Close(false, false)
Marshal.FinalReleaseComObject(xlWorkBook)
End If
xlApp.Quit()
Marshal.FinalReleaseComObject(xlApp)
答案很長:讀到另一個問題的答案 (整篇文章也很有幫助)。
我遇到了這個問題,我發現的工作是確保我在所有Workbook和Workbooks對象上調用Close()方法,以及在Excel Application對象上調用Quit()方法。 我還在實例化每個Excel對象上調用System.Runtime.InteropServices.Marshal.ReleaseComObject。 我按照年齡的相反順序完成所有這些操作,因此最新的對象首先被清理,而最舊的對象(即Application對象)將被最后處理。 我不知道訂單是否真的重要,但似乎可能。
我已經看到了最后調用GC.Collect()的示例,但我從來沒有必要這樣做以使excel.exe進程結束。
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