csharp read excel file get sheetName list

        /// <summary>
        ///      
        /// 塗聚文
        /// 20120803
        /// Geovin Du
        ///找到EXCEL的工作表名称 要考慮打開的文件的進程問題
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="comboBox2"></param>
        /// <returns></returns>
        public static System.Data.DataTable getSheetName(string filename, ComboBox comboBox2)
        {
            System.Data.DataTable dtSheets = new System.Data.DataTable();
            try
            {
                
                dtSheets.Columns.Add("id", typeof(int));
                dtSheets.Columns.Add("SheetName", typeof(string));            
                object objOpt = Missing.Value;
                Excel.Application excelApp = new Excel.Application();
                excelApp.Workbooks.Open(filename, objOpt, objOpt, objOpt, objOpt, objOpt, true, objOpt, objOpt, true, objOpt, objOpt, objOpt, objOpt, objOpt);
                for (int i = 0; i < excelApp.Workbooks[1].Worksheets.Count; i++)
                {
                    Excel.Worksheet ws = (Excel.Worksheet)excelApp.Workbooks[1].Worksheets[i + 1];
                    string sSheetName = ws.Name;
                    dtSheets.Rows.Add(i, ws.Name);
                }
                comboBox2.DataSource = dtSheets;
                comboBox2.DisplayMember = "SheetName";
                comboBox2.ValueMember = "id";
                comboBox2.AutoCompleteMode = AutoCompleteMode.Suggest;
                comboBox2.AutoCompleteSource = AutoCompleteSource.ListItems;
                KillExcelProceed();
                Kill(excelApp);
            }
            catch (IOException ex)
            {
                ex.Message.ToString();
            }
            return dtSheets;
        }
        /// <summary>
        ///      
        /// 塗聚文 締友計算機信息技術有限公司
        /// 20120803
        /// Geovin Du
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="comboBox2"></param>
        /// <returns></returns>
        public static System.Data.DataTable getGeovinDuSheetName(string filename, ComboBox comboBox2)
        {
            System.Data.DataTable dtSheets = new System.Data.DataTable();
            

            try
            {

                dtSheets.Columns.Add("id", typeof(int));
                dtSheets.Columns.Add("SheetName", typeof(string));
                string connectionString = String.Format(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties=""Excel 8.0;HDR=YES;IMEX=1;""", filename); //高版本用：Microsoft.ACE.OLEDB.12.0
                DbProviderFactory factory = DbProviderFactories.GetFactory("System.Data.OleDb");
                DbConnection connection = factory.CreateConnection();
                connection.ConnectionString = connectionString;
                connection.Open();
                DataTable tbl = connection.GetSchema("Tables");
                connection.Close();
                int i = 0;
                foreach (DataRow row in tbl.Rows)
                {
                    string sheetName = (string)row["TABLE_NAME"];
                    if (sheetName.EndsWith("$"))
                    {
                        sheetName = sheetName.Substring(0, sheetName.Length - 1);
                    }
                    //繁體系統需要此操作，簡體的不需要也可以
                    sheetName = sheetName.Replace("$", "");
                    sheetName = sheetName.Replace("'", "");
                    dtSheets.Rows.Add(i,sheetName.Replace("$", ""));
                    i++;
                }
                comboBox2.DataSource = dtSheets;
                comboBox2.DisplayMember = "SheetName";
                comboBox2.ValueMember = "id";
                comboBox2.AutoCompleteMode = AutoCompleteMode.Suggest;
                comboBox2.AutoCompleteSource = AutoCompleteSource.ListItems;

                return dtSheets;
            }
            catch (IOException ex)
            {
                ex.Message.ToString();
                return null;
            }
                
        }