HOWTO: Use MFC to Automate Excel and Obtain an Array from a Range

• Microsoft Visual C++, 32-bit Editions, versions 5.0, 6.0
• Microsoft Excel 97 for Windows
• Microsoft Office 2000 Developer
• Microsoft Excel 2000

SUMMARY

This article demonstrates how to automate Microsoft Excel 97 and return the values from a multi-cell range to an array.

MORE INFORMATION

To return the values from a multi-cell range without querying the cells one-by-one, you must use the GetValue member function of the Range object to return the values to a VARIANT. You then construct a SAFEARRAY based on the VARIANT you returned from GetValue. Once you have the SAFEARRAY, you can access the elements using GetElement. The following steps illustrate this process and demonstrate how you can access both string and numeric elements.

Notes for Automating Microsoft Excel 2000:

Some methods and properties have changed for Microsoft Excel 2000. For additional information about using the sample code described in this article with the Microsoft Excel 2000 type library, please see the following article in the Microsoft Knowledge Base:

Q224925 INFO: Type Libraries for Office 2000 Have Changed

Steps to Create Project

1. In Microsoft Excel, create a new workbook. Populate cells A1:C8 with a mixture of string and numeric data. Save the workbook as "c:\test.xls" and exit Microsoft Excel.



2. Follow steps 1 through 12 in the following article in the Microsoft Knowledge Base to create a sample project that uses the IDispatch interfaces and member functions defined in the Excel8.olb type library:




Q178749 HOWTO: Create an Automation Project Using MFC and a Type Library

3. At the top of the AutoProjectDlg.cpp file, add the following line:




      #include "excel8.h" 

4. Add the following code to CAutoProjectDlg::OnRun() in the AutoProjectDlg.cpp file:




Sample Code

      // OLE Variant for Optional.
      COleVariant VOptional((long)DISP_E_PARAMNOTFOUND, VT_ERROR);

      _Application objApp;
      _Workbook objBook;
      Workbooks objBooks;
      Worksheets objSheets;
      _Worksheet objSheet;
      Range objRange;
      VARIANT ret;

      // Instantiate Excel and open an existing workbook.
      objApp.CreateDispatch("Excel.Application");
      objBooks = objApp.GetWorkbooks();
      objBook = objBooks.Open("C:\\Test.xls",
                VOptional, VOptional, VOptional, VOptional,
                VOptional, VOptional, VOptional, VOptional,
                VOptional, VOptional, VOptional, VOptional);
      objSheets = objBook.GetWorksheets();
      objSheet = objSheets.GetItem(COleVariant((short)1));

      //Get the range object for which you wish to retrieve the
      //data and then retrieve the data (as a variant array, ret).
      objRange = objSheet.GetRange(COleVariant("A1"), COleVariant("C8"));
      ret = objRange.GetValue();

      //Create the SAFEARRAY from the VARIANT ret.
      COleSafeArray sa(ret);

      //Determine the array's dimensions.
      long lNumRows;
      long lNumCols;
      sa.GetUBound(1, &lNumRows);
      sa.GetUBound(2, &lNumCols);

      //Display the elements in the SAFEARRAY.
      long index[2];
      VARIANT val;
      int r, c;
      TRACE("Contents of SafeArray\n");
      TRACE("=====================\n\t");
      for(c=1;c<=lNumCols;c++)
      {
         TRACE("\t\tCol %d", c);
      }
      TRACE("\n");
      for(r=1;r<=lNumRows;r++)
      {
         TRACE("Row %d", r);
         for(c=1;c<=lNumCols;c++)
         {
            index[0]=r;
            index[1]=c;
            sa.GetElement(index, &val);
            switch(val.vt)
            {
            case VT_R8:
               {
                  TRACE("\t\t%1.2f", val.dblVal);
                  break;
               }
            case VT_BSTR:
               {
                  TRACE("\t\t%s",(CString)val.bstrVal);
                  break;
               }
            case VT_EMPTY:
               {
                  TRACE("\t\t<empty>");
                  break;
               }
            }
         }
         TRACE("\n");
      }

      //Close the workbook without saving changes
      //and quit Microsoft Excel.
      objBook.Close(COleVariant((short)FALSE), VOptional, VOptional);
      objApp.Quit(); 

5. Compile the project and run it.



6. Click Run. The values in cells A1:C8 are displayed in the Output window.

REFERENCES

For additional information about automating Microsoft Excel using MFC, please click the article numbers below to view the articles in the Microsoft Knowledge Base:

Q186120 HOWTO: Use MFC to Automate Excel and Fill a Range with an Array

Q184663 HOWTO: Embed and Automate a Microsoft Excel Worksheet with MFC

Q179706 HOWTO: Use MFC to Automate Excel and Create/Format a New Workbook

Q178781 HOWTO: Automate Excel 97 Using MFC and Worksheet Functions

Q178783 HOWTO: Use MFC to Create a Microsoft Excel 97 Chart

Q167668 HOWTO: Pass a SafeArray of Strings in a VARIANT

Additional query words:

Keywords : kbcode kbinterop kbole kbAutomation kbMFC kbVC500 kbVC600 kbOffice2000 kbExcel97 kbDSupport kbexcel2000
Version : WINDOWS:2000; winnt:5.0,6.0; :
Platform : WINDOWS winnt
Issue type : kbhowto