Problem to Embedded statement

                        string vIT = "";
                        int index = InsertSharedStringItem(vIT, shareStringPart);

        private static int InsertSharedStringItem(string text, SharedStringTablePart shareStringPart)
        {
            if (shareStringPart.SharedStringTable == null)
            {
                shareStringPart.SharedStringTable = new SharedStringTable();
            }

            int i = 0;
            foreach (SharedStringItem item in shareStringPart.SharedStringTable.Elements<SharedStringItem>())
            {
                if (item.InnerText == text)
                {
                    return i;
                }

                i++;
            }
            shareStringPart.SharedStringTable.AppendChild(new SharedStringItem(new DocumentFormat.OpenXml.Spreadsheet.Text(text)));
            shareStringPart.SharedStringTable.Save();
            return i;
        }

Many Thanks & Best Regards, Hua Min