释放Interop Excel对象

Question

I'm currently writting a C#.NET application who use a VBA macro in an Excel file.

I run the macro from the c# application when the user click on a button. I have to wait all data are downloaded that's why this is the VBA code who execute "Application.Quit".

There is my code :

private void toolStripButton5_Click(object sender, EventArgs e)
    {
        int lastUsedRowFund, lastUsedRowEquity, lastUsedRowBond, lastUsedRowAccount = 0;

        Excel.Application oXL = new Microsoft.Office.Interop.Excel.Application();
        Excel.Workbook oWB = null;
        Excel.Worksheet oSheetFund = null;
        Excel.Worksheet oSheetEquity = null;
        Excel.Worksheet oSheetBond = null;
        Excel.Worksheet oSheetAccount = null;

        oXL.Visible = false;

        oWB = oXL.Workbooks.Open("C:\\extract.xlsm");

        oSheetFund = oWB.Sheets["Fund"];
        oSheetEquity = oWB.Sheets["Equity"];
        oSheetBond = oWB.Sheets["Bond"];
        oSheetAccount = oWB.Sheets["Account"];

        string[] valuesHeaderFund = {"field1", "field2" };

        string[] valuesHeaderEquity = {"field1", "field2"};

        string[] valuesHeaderBond = {"field1", "field2"};

        string[] valuesHeaderAccount = {"field1", "field2"};

        Excel.Range headerFund = oSheetFund.get_Range("A1", "AA1");
        Excel.Range headerEquity = oSheetEquity.get_Range("A1", "AE1");
        Excel.Range headerBond = oSheetBond.get_Range("A1", "AE1");
        Excel.Range headerAccount = oSheetAccount.get_Range("A1", "AE1");

        headerFund.Value2 = valuesHeaderFund;
        headerEquity.Value2 = valuesHeaderEquity;
        headerBond.Value2 = valuesHeaderBond;
        headerAccount.Value2 = valuesHeaderAccount;

        Excel.Range lastRowFund = oSheetFund.Cells.SpecialCells(Excel.XlCellType.xlCellTypeLastCell, Type.Missing);
        Excel.Range lastRowEquity = oSheetEquity.Cells.SpecialCells(Excel.XlCellType.xlCellTypeLastCell, Type.Missing);
        Excel.Range lastRowBond = oSheetBond.Cells.SpecialCells(Excel.XlCellType.xlCellTypeLastCell, Type.Missing);
        Excel.Range lastRowAccount = oSheetAccount.Cells.SpecialCells(Excel.XlCellType.xlCellTypeLastCell, Type.Missing);

        lastUsedRowFund = lastRowFund.Row;
        lastUsedRowEquity = lastRowEquity.Row;
        lastUsedRowBond = lastRowBond.Row;
        lastUsedRowAccount = lastRowAccount.Row;

        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            string[] data = { row.Cells[0].Value.ToString(), row.Cells[1].Value.ToString()};

            if (row.Cells[5].Value.ToString() == "FON")
            {

                lastUsedRowFund += 1;
                oSheetFund.get_Range("A" + lastUsedRowFund, "K" + lastUsedRowFund).Value2 = data;

            }
            else if (row.Cells[5].Value.ToString() == "ACT")
            {

                lastUsedRowEquity += 1;
                oSheetEquity.get_Range("A" + lastUsedRowEquity, "K" + lastUsedRowEquity).Value2 = data;

            }
            else if (row.Cells[5].Value.ToString() == "OBL")
            {

                lastUsedRowBond += 1;
                oSheetBond.get_Range("A" + lastUsedRowBond, "K" + lastUsedRowBond).Value2 = data;

            }
            else if (row.Cells[5].Value.ToString() == "ACCOUNT")
            {

                lastUsedRowAccount += 1;
                oSheetAccount.get_Range("A" + lastUsedRowAccount, "K" + lastUsedRowAccount).Value2 = data;

            }
        }

        RunMacro(oXL, new Object[] { "Main" });

        oXL.UserControl = false;

        //oWB.Close();
        //oXL.Quit();

        releaseObject(lastRowFund);
        releaseObject(lastRowEquity);
        releaseObject(lastRowBond);
        releaseObject(lastRowAccount);
        releaseObject(headerFund);
        releaseObject(headerEquity);
        releaseObject(headerBond);
        releaseObject(headerAccount);
        releaseObject(oSheetFund);
        releaseObject(oSheetEquity);
        releaseObject(oSheetBond);
        releaseObject(oSheetAccount);
        releaseObject(oWB);
        releaseObject(oXL);

    private void RunMacro(object oApp, object[] oRunArgs)
    {
        oApp.GetType().InvokeMember("Run",
            System.Reflection.BindingFlags.Default |
            System.Reflection.BindingFlags.InvokeMethod,
            null, oApp, oRunArgs);
    }

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

When i click on the toolStripButton5, everything is working. But at the end an "EXCEL.EXE" processus still alive in task manager. When i click again on the button, a new "EXCEL.EXE" is create but when the task is finish, the processus is correctly release. When i quit my application, the first processus is release.

Can you help me to correctly release the object at the first click.

Regards,

Danny.

Answer 1

Unfortunatelly this is not so simple to quit Excel app, because COM objects of Interoop services still exists in memory. That's why Excel.exe process is still running. Every object can be released using Marshal class. Sample codes:

Marshal.ReleaseComObject(excelSheets);   //Worksheet
Marshal.ReleaseComObject(excelSheet);    //Sheet

...and so on. Hope this helps.

Answer 2

Now, it works greatly. When i execute a second extraction with Excel, the first process is correctly release when the new one is created.

I just replace in "releaseObject" System.Runtime.InteropServices.Marshal.ReleaseComObject(obj); by Marshal.ReleaseComObject(obj);

Maybe because i use "using System.Runtime.InteropServices;" in the header.

Thanks a lot.

Regards