Chart refresh issue using microsoft.office.word.interop

//Create an instance for word app  
            Microsoft.Office.Interop.Word.Application winword = new Microsoft.Office.Interop.Word.Application();

            //Set animation status for word application  
            winword.ShowAnimation = false;

            //Set status for word application is to be visible or not.  
            winword.Visible = false;

            //Create a missing variable for missing value  
            object missing = System.Reflection.Missing.Value;

            //Create a new document  
            Microsoft.Office.Interop.Word.Document document = winword.Documents.Add(ref missing, ref missing, ref missing, ref missing);


            object bookmarkName = "PlaceChartHere";
            //var wrdRng = document.Bookmarks.get_Item(ref bookmarkName).Range;
            Microsoft.Office.Interop.Word.InlineShape wrdInlineShape1 = document.InlineShapes.AddChart2(-1, XlChartType.xlColumnStacked);

            var chartStackedCol = wrdInlineShape1.Chart;

            chartStackedCol.ChartTitle.Text = "Chart Title";

            Microsoft.Office.Interop.Excel.Workbook obook1 = (Microsoft.Office.Interop.Excel.Workbook)chartStackedCol.ChartData.Workbook;
            Microsoft.Office.Interop.Excel.Worksheet sheet1 = (Microsoft.Office.Interop.Excel.Worksheet)obook1.Worksheets["Sheet1"];

            ((Microsoft.Office.Interop.Excel.Range)sheet1.Cells[1, 2]).Value = "Data1";
            ((Microsoft.Office.Interop.Excel.Range)sheet1.Cells[1, 3]).Value = "Data2";
            ((Microsoft.Office.Interop.Excel.Range)sheet1.Cells[1, 4]).Value = "Data3";

            ((Microsoft.Office.Interop.Excel.Range)sheet1.Cells[2, 1]).Value = "Test1";
            ((Microsoft.Office.Interop.Excel.Range)sheet1.Cells[3, 1]).Value = "Test2";

            sheet1.Range["B2"].FormulaR1C1 = 100;
            sheet1.Range["B3"].FormulaR1C1 = 204;

            sheet1.Range["C2"].FormulaR1C1 = 30;
            sheet1.Range["C3"].FormulaR1C1 = 40;

            sheet1.Range["D2"].FormulaR1C1 = 1;
            sheet1.Range["D3"].FormulaR1C1 = 620;


            chartStackedCol.ChartData.Activate();
            chartStackedCol.Refresh();
            winword.ScreenUpdating = true;
            document.Application.ScreenRefresh();

            //Save the document  
            object filename = AppDomain.CurrentDomain.BaseDirectory + "Chartrefresh.docx";
            document.SaveAs2(ref filename);
            document.Close(ref missing, ref missing, ref missing);
            document = null;
            winword.Quit(ref missing, ref missing, ref missing);
            winword = null;
            MessageBox.Show("Document created successfully !");