Re: Automation and XLL add-ins

From:
Lynn McGuire <lmc@winsim.com>
Newsgroups:
comp.lang.c++,microsoft.public.excel.programming
Date:
Fri, 15 Oct 2010 17:18:12 -0500
Message-ID:
<i9ajva$rch$2@news.eternal-september.org>

I'm developing an add-in in C++ using the Excel 2010 XLL SDK, and in
the process I have to return values to other cells than the one the
function in entered into. To that end, I think Automation might work.
I've managed to get automation to work inside the UDF, using the
following:
http://support.microsoft.com/kb/216686
The problem, however, is that the program opens a new instance of
Excel, creates a new worksheet and puts data into that. I wish to put
the data onto the sheet on which the UDF was entered - not a new sheet
in a new workbook. How might I achieve this goal?


And this is how you open an existing sheet in a notebook:

int ConnectToNewSheet (std::string newSheetName, int createNewSheet, std::string baseSheetName, int deleteExistingSheet)
{
    int sheetDeleted = FALSE;
    int sheetOpenAlready = false;
    IDispatch * pExcelSheets = NULL;

        // get the names of the currently open sheets and see if this one is open already
        // otherwise add the sheet and rename it
    VARIANT result1;
    VariantInit ( & result1);
    OLEMethod (DISPATCH_PROPERTYGET, & result1, pExcelWorkbook, L"Sheets",
                "Getting the pointer to the Sheets collection in the active spreadsheet (ConnectToNewSheet)", 0);
    if (result1.vt == VT_DISPATCH)
    {
        pExcelSheets = result1.pdispVal;
        VARIANT result2;
        VariantInit ( & result2);
        OLEMethod (DISPATCH_PROPERTYGET, & result2, pExcelSheets, L"Count",
                    "Get the number of sheets in the spreadsheet (ConnectToNewSheet)", 0);
        int numberOfSheets = 0;
        if (result2.vt == VT_I4)
            numberOfSheets = result2.intVal;
        if (numberOfSheets > 0)
        {
            for (int i = 0; i < numberOfSheets && ! sheetOpenAlready; i++)
            {
                VARIANT result3;
                VariantInit ( & result3);
                VARIANT itemNumber;
                itemNumber.vt = VT_I4;
                    // put the index of the workbook to get into the variant, the index starts with 1
                itemNumber.intVal = i + 1;
                OLEMethod (DISPATCH_PROPERTYGET, & result3, pExcelSheets, L"Item",
                            "Set the index of the sheet of the active spreadsheet (ConnectToNewSheet)", 1, itemNumber);
                if (result3.vt == VT_DISPATCH)
                {
                    IDispatch *pDisp = result3.pdispVal;
                    VARIANT result4;
                    VariantInit ( & result4);
                    OLEMethod (DISPATCH_PROPERTYGET, & result4, pDisp, L"Name",
                                "Get the name of the indexed sheet of the spreadsheet (ConnectToNewSheet)", 0);
                    if (result4.vt == VT_BSTR)
                    {
                            // this will be the sheet name
                        std::string sheetName = _bstr_t (result4.bstrVal);
                        if (sheetName == newSheetName)
                        {
                            sheetOpenAlready = true;
                                // if there is a current excel sheet then release it
                            if (pExcelSheet)
                            {
                                pExcelSheet -> Release ();
                                pExcelSheet = NULL;
                            }
                                // copy the dispatch pointer to the workbook pointer
                            pExcelSheet = pDisp;
                            VARIANT result5;
                            VariantInit ( & result5);
                            OLEMethod (DISPATCH_PROPERTYGET, & result5, pDisp, L"Activate",
                                        "Activate the sheet of the spreadsheet (ConnectToNewSheet)", 0);
                            int res = result5.vt;
                            if (deleteExistingSheet)
                            {
                                sheetOpenAlready = false;
                                pExcelSheet = NULL;
                                    // gotta turn off the display alerts or will get a message from excel asking if it can delete
                                VARIANT result6;
                                VariantInit ( & result6);
                                VARIANT displayAlerts;
                                VariantInit ( & displayAlerts);
                                displayAlerts.vt = VT_BOOL;
                                displayAlerts.boolVal = false;
                                OLEMethod (DISPATCH_PROPERTYPUT, & result6, pExcelApplication, L"DisplayAlerts",
                                            "Turn display alerts off so we can delete a sheet in silence (ConnectToNewSheet)",
                                            1, displayAlerts);
                                int res6 = result6.vt;
                                VARIANT result7;
                                VariantInit ( & result7);
                                OLEMethod (DISPATCH_PROPERTYGET, & result7, pDisp, L"Delete",
                                            "Delete the current sheet in the spreadsheet (ConnectToNewSheet)", 0);
                                int res7 = result7.vt;
                                    // gotta turn off the display alerts or will get a message from excel asking if it can delete
                                VARIANT result8;
                                VariantInit ( & result8);
                                VARIANT displayAlerts8;
                                VariantInit ( & displayAlerts8);
                                displayAlerts8.vt = VT_BOOL;
                                displayAlerts8.boolVal = true;
                                OLEMethod (DISPATCH_PROPERTYPUT, & result8, pExcelApplication, L"DisplayAlerts",
                                            "Turn display alerts back on after deleting a sheet in the spreadsheet (ConnectToNewSheet)",
                                            1, displayAlerts8);
                                int res8 = result8.vt;
                                pDisp -> Release ();
                                    // get out of this for loop since we are finished with it
                                break;
                            }
                        }
                        else
                            pDisp -> Release ();
                    }
                }
            }
        }
    }
    else
        return false;

        // we need to create the sheet file if not done already
    if ( ! sheetOpenAlready && pExcelSheets && createNewSheet)
    {
        pExcelSheets = result1.pdispVal;
        VARIANT result2;
        VariantInit ( & result2);
        OLEMethod (DISPATCH_PROPERTYGET, & result2, pExcelSheets, L"Count",
                    "Getting the number of sheets in the active spreadsheet (ConnectToNewSheet)", 0);
        int numberOfSheets = 0;
        if (result2.vt == VT_I4)
            numberOfSheets = result2.intVal;
        if (numberOfSheets > 0)
        {
            for (int i = 0; i < numberOfSheets && ! sheetOpenAlready; i++)
            {
                VARIANT result3;
                VariantInit ( & result3);
                VARIANT itemNumber;
                itemNumber.vt = VT_I4;
                    // put the index of the workbook to get into the variant, the index starts with 1
                itemNumber.intVal = i + 1;
                OLEMethod (DISPATCH_PROPERTYGET, & result3, pExcelSheets, L"Item",
                            "Set the index of the active sheet of the spreadsheet (ConnectToNewSheet)", 1, itemNumber);
                if (result3.vt == VT_DISPATCH)
                {
                    IDispatch *pDisp = result3.pdispVal;
                    VARIANT result4;
                    VariantInit ( & result4);
                    OLEMethod (DISPATCH_PROPERTYGET, & result4, pDisp, L"Name",
                                "Get the name of the indexed sheet of the active spreadsheet (ConnectToNewSheet)", 0);
                    if (result4.vt == VT_BSTR)
                    {
                            // this will be the sheet name
                        std::string sheetName = _bstr_t (result4.bstrVal);
                        if (sheetName == baseSheetName)
                        {
                            sheetOpenAlready = true;
                                // if there is a current excel sheet then release it
                            if (pExcelSheet)
                            {
                                pExcelSheet -> Release ();
                                pExcelSheet = NULL;
                            }
                                // copy the dispatch pointer to the workbook pointer
                            pExcelSheet = pDisp;
                            VARIANT result5;
                            VariantInit ( & result5);
                            OLEMethod (DISPATCH_PROPERTYGET, & result5, pDisp, L"Activate",
                                        "Set the spreadsheet back to the sheet in the active spreadsheet (ConnectToNewSheet)", 0);
                            int res = result5.vt;
                        }
                        else
                            pDisp -> Release ();
                    }
                }
            }
        }
            // now create the new sheet, hopefully in the proper place
        VARIANT result3;
        VariantInit ( & result3);
        OLEMethod (DISPATCH_METHOD, & result3, pExcelSheets, L"Add",
                    "Add a new sheet to the active spreadsheet (ConnectToNewSheet)", 0);
            // copy the dispatch pointer to the sheet pointer
        if (result3.vt == VT_DISPATCH)
        {
                // if there is a current excel sheet then release it
            if (pExcelSheet)
            {
                pExcelSheet -> Release ();
                pExcelSheet = NULL;
            }
            pExcelSheet = result3.pdispVal;
                // now name the sheet to the new name
            VARIANT result4;
            VariantInit ( & result4);
            VARIANT fnameNew;
            fnameNew.vt = VT_BSTR;
            _bstr_t sheetNameNewBstr = _bstr_t (newSheetName.c_str ());
            fnameNew.bstrVal = sheetNameNewBstr;
            OLEMethod (DISPATCH_PROPERTYPUT, & result4, pExcelSheet, L"Name",
                        "Set the name of the new sheet in the active spreadsheet (ConnectToNewSheet)", 1, fnameNew);
            int res = result4.vt;
        }
        else
            return false;
    }

    if (pExcelSheets)
        pExcelSheets -> Release ();

    return true;
}

Lynn

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