C#使用Excel进程销毁多个Excel对象的正确方法

Question

我有一个C#控制台程序.运行时,它会实例化一些Excel对象,例如:(openExcelO).

当程序运行完毕后,我有一个关闭Excel(closeExcel)的方法,它应该正确地清理Excel进程.在任务管理器中,我可以看到剩余的Excel残余.关闭例程从互联网示例拼凑而成:

    private void openExcelO (string dir) {

        try {
            xlApp = new Excel.Application();
            xlWorkBook = xlApp.Workbooks.Open(dir + "PortfolioOptimization5.xlsm",
                0, false, 5, "", "", true, 
                Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, 
                "\t", false, false, 0, true, 1, 0);
            xlMarkowitz = (Excel.Worksheet)xlWorkBook.Sheets["Markowitz"];
            xlWeights = (Excel.Worksheet)xlWorkBook.Sheets["Weights"];

        } catch (Exception ex) {
            ReportError("PortfolioOptimization", "openExcel", ex.ToString());
        }

    }


    private void closeExcel () {
        object misValue = System.Reflection.Missing.Value;
        try {

            if (xlWeights != null) releaseObject(xlWeights);
            if (xlMarkowitz != null) releaseObject(xlMarkowitz);

            xlWorkBook.Close(false, misValue, misValue);
            if (xlApp != null) xlApp.Quit();

            if (xlWorkBook != null) releaseObject(xlWorkBook);
            if (xlApp != null) releaseObject(xlApp);

        } catch (Exception ex) {
            ReportError("PortfolioOptimization", "closeExcel", ex.ToString());
        }
    }


    private void releaseObject (object obj) {
        try {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
            obj = null;
        } catch (Exception ex) {
            obj = null;
            ReportError("PortfolioOptimization", "releaseObject", "Unable to release object " + ex.ToString());
        } finally {
            GC.Collect();
        }
    }

如何更改关闭例程以正确关闭和清理Excel对象,以便任务管理器中没有延迟的Excel进程？

谢谢!

Answer 1

看起来你没有以正确的顺序发布你的对象 - xlApp.Quit可能无法干净地退出,因为你仍然持有对工作簿的引用.您需要在调用之前释放工作簿Quit:

xlWorkBook.Close(false, misValue, misValue);
releaseObject(xlWorkBook);

xlApp.Quit();
releaseObject(xlApp);

信用必须转到此StackOverflow答案:还有一些其他隐式引用,您没有关闭,即,在以下行中:

xlWorkBook = xlApp.Workbooks.Open(...)
xlWorkBook.Sheets["Markowitz"];

"Workbooks"对象未发布,"Sheets"对象也未发布.您还需要发布这些引用,即:

var books = xlApp.Workbooks;
books.Open(...);
releaseObject(books);

var sheets = xlWorkBook.Sheets;
xlMarkowitz = (Excel.Worksheet)sheets["Markowitz"];
xlWeights = (Excel.Worksheet)sheets["Weights"];
releaseObject(sheets);

从大的意见布鲁斯·巴克:"不要用两个点与COM对象"!