How to export projects layerwise in Microsoft Dynamics AX 2012

static void exportProjects(Args _args)
{
    #AotExport
    TreeNodeIterator        tni;
    ProjectNode             projectNode;
    int                     exportFlag;
    Dialog                  dialog = new Dialog();
    DialogField             folderName;
    DialogField             projectDefinitionOnly;
    DialogField             exportFromLayer;
    DialogField             projectType;
    UtilEntryLevel          layer;

    SysExcelApplication     application;
    SysExcelWorkbooks       workbooks;
    SysExcelWorkbook        workbook;
    SysExcelWorksheets      worksheets;
    SysExcelWorksheet       worksheet;
    SysExcelCells           cells;
    SysExcelCell            cell;
    SysExcelFont            font;
    int                     row;
    CustTable               custTable;
    str                     fileName;

    fileName    = "D:\\Backup XPOs.xlsx"; //By specifying the directly, we will get the list of exported projects
    //Excel Part..............................................................................

    dialog.addText("This will export all projects (shared or private) that exist in a selected model.");
    projectType             = dialog.addFieldValue(enumStr(ProjectSharedPrivate), ProjectSharedPrivate::ProjShared);
    projectDefinitionOnly   = dialog.addField(extendedTypeStr(NoYesId), 'Project Definition Only');
    folderName              = dialog.addField(extendedTypeStr(FilePath));
    exportFromLayer         = dialog.addField(enumStr(UtilEntryLevel), 'Projects from layer');

    dialog.run();

    if (dialog.closedOk())
    {
        if (!folderName.value())
            throw error("Missing folder");

        exportFlag = #export;
        if (projectDefinitionOnly.value())
            exportFlag += #expProjectOnly;

        layer = exportFromLayer.value();
        
        switch (projectType.value())
        {
            case ProjectSharedPrivate::ProjPrivate:
                tni = SysTreeNode::getPrivateProject().AOTiterator();
                break;

            case ProjectSharedPrivate::ProjShared:
                tni = SysTreeNode::getSharedProject().AOTiterator();
                break;
        }

        projectNode = tni.next() as ProjectNode;

        while (projectNode)
        {
            if (projectNode.AOTLayer() == layer && projectNode.name() like "CFS*") //if [like] specifies, system will export the projects which names starts with CFS
            {
                projectNode.treeNodeExport(folderName.value() + '\\' + projectNode.name() + '.xpo', exportFlag);

                row++;
            }

            projectNode = tni.next() as ProjectNode;
        }

        info("Projects Exported Successfully & Exported Projects List to Excel Sheet");
    }
    else
        warning("No action taken...");
}