Excel.Worksheet activeWorksheet = ((Excel.Worksheet)Globals.ThisAddIn.Application.ActiveSheet);

        foreach (PivotTable pt in activeWorksheet.PivotTables())
        {
            foreach (PivotField pf in pt.PivotFields())
            {
                if (pf.Name == "Year" && pf.Orientation == Excel.XlPivotFieldOrientation.xlPageField)
                {
                    //pf.CubeField.EnableMultiplePageItems = true;
                    //pf.ClearAllFilters();
                    //  pf.CurrentPageName = arr.ToString();
                    //  pf.CurrentPage = "(All)";
                    string[] ar = new string[3] { "2014", "2015", "2016" };

                   // pf.CurrentPageList = ar;
                    pf.VisibleItemsList = ar;
                }
            }
            pt.ManualUpdate = false;
        }