互操作过程后无法关闭 Excel.exe [英] Cannot close Excel.exe after Interop process

问题描述

我在使用 Excel Interop 时遇到问题.

I'm having an issue with Excel Interop.

即使我释放实例，Excel.exe 也不会关闭.

The Excel.exe doesn't close even if when I realease instances.

这是我的代码:

using xl = Microsoft.Office.Interop.Excel;


xl.Application excel = new xl.Application();
excel.Visible = true;
excel.ScreenUpdating = false;
if (wordFile.Contains(".csv") || wordFile.Contains(".xls"))
{
   //typeExcel become a string of the document name
   string typeExcel = wordFile.ToString();
   xl.Workbook workbook = excel.Workbooks.Open(typeExcel,
                                                oMissing,  oMissing,  oMissing,  oMissing,
                                                oMissing,  oMissing,  oMissing,  oMissing,
                                                oMissing,  oMissing,  oMissing,  oMissing,
                                                oMissing,  oMissing);
   object outputFileName = null;
   if (wordFile.Contains(".xls"))
   {
     outputFileName = wordFile.Replace(".xls", ".pdf");
   }
   else if (wordFile.Contains(".csv"))
   {
     outputFileName = wordFile.Replace(".csv", ".pdf");
   }

   workbook.ExportAsFixedFormat(XlFixedFormatType.xlTypePDF, outputFileName, 
                                 XlFixedFormatQuality.xlQualityStandard, oMissing,
                                 oMissing, oMissing, oMissing, oMissing, oMissing);

   object saveChanges = xl.XlSaveAction.xlDoNotSaveChanges;
   ((xl._Workbook)workbook).Close(saveChanges, oMissing, oMissing);

   Marshal.ReleaseComObject(workbook);
   workbook = null;
}

我看到，使用 Marshal.RealeaseComObject 它应该可以工作，但没有.我该如何解决这个问题?

I saw that, with the Marshal.RealeaseComObject it should be work, but nothing. How can I fix this?

谢谢.

推荐答案

简单规则:避免使用双点调用表达式，例如:

Simple rule: avoid using double-dot-calling expressions, such as this:

var workbook = excel.Workbooks.Open(/*params*/)

...因为通过这种方式您可以创建 RCW 对象不仅用于 workbook，还用于 Workbooks，你也应该释放它(如果没有维护对对象的引用，这是不可能的).

...because in this way you create RCW objects not only for workbook, but for Workbooks, and you should release it too (which is not possible if a reference to the object is not maintained).

所以，正确的方法是:

var workbooks = excel.Workbooks;
var workbook = workbooks.Open(/*params*/)

//business logic here

Marshal.ReleaseComObject(workbook);
Marshal.ReleaseComObject(workbooks);
Marshal.ReleaseComObject(excel);

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