csharp: read excel using Aspose.Cells

 /// <summary>
        /// 
        /// </summary>
        /// <param name="strFileName"></param>
        /// <returns></returns>
        public static System.Data.DataTable ReadExcel(String strFileName)
        {
            Workbook book = new Workbook(strFileName);
            //book.Open(strFileName); // 
            Worksheet sheet = book.Worksheets[0];
            
            Cells cells = sheet.Cells;

            return cells.ExportDataTableAsString(0, 0, cells.MaxDataRow + 1, cells.MaxDataColumn + 1, true);
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="strFileName"></param>
        /// <param name="sheetname"></param>
        /// <returns></returns>
        public static System.Data.DataTable ReadExcel(String strFileName,string sheetname)
        {
            Workbook book = new Workbook(strFileName);
            //book.Open(strFileName);// 
            Worksheet sheet = book.Worksheets[sheetname];

            Cells cells = sheet.Cells;

            return cells.ExportDataTableAsString(0, 0, cells.MaxDataRow + 1, cells.MaxDataColumn + 1, true);
        }
        /// <summary>
        ///  
        ///  
        /// 20150228
        /// </summary>
        /// <param name="strFileName"></param>
        /// <param name="comb"></param>
        public static void ReadExcelCombox(String strFileName, System.Windows.Forms.ComboBox comb)
        {
            comb.Items.Clear();
            Workbook book = new Workbook(strFileName);
            // book.Open(strFileName);// 
            Worksheet sheet = book.Worksheets[0];
            for (int i = 0; i < book.Worksheets.Count; i++)
            {
                comb.Items.Add(book.Worksheets[i].Name.ToString());  
            }
           // Cells cells = sheet.Cells;

            //return cells.ExportDataTableAsString(0, 0, cells.MaxDataRow + 1, cells.MaxDataColumn + 1, true);
        }

        /// <summary>
        /// DataTable EXCEL
        /// http://www.aspose.com/docs/display/cellsnet/Aspose.Cells+Object+Model
        /// http://www.aspose.com/docs/display/cellsnet/Converting+Worksheet+to+Image+and+Worksheet+to+Image+by+Page
        /// </summary>
        /// <param name="datatable"></param>
        /// <param name="filepath"></param>
        /// <param name="error"></param>
        /// <returns></returns>
        public static bool DataTableToExcel(DataTable datatable, string filepath, out string error)
        {
            error = "";
            try
            {
                if (datatable == null)
                {
                    error = "DataTableToExcel:datatable  ";
                    return false;
                }

                Aspose.Cells.Workbook workbook = new Aspose.Cells.Workbook();
                Aspose.Cells.Worksheet sheet = workbook.Worksheets[0];
                Aspose.Cells.Cells cells = sheet.Cells;

                int nRow = 0;
                foreach (DataRow row in datatable.Rows)
                {
                    nRow++;
                    try
                    {
                        for (int i = 0; i < datatable.Columns.Count; i++)
                        {
                            if (row[i].GetType().ToString() == "System.Drawing.Bitmap")
                            {
                                //------ -------
                                System.Drawing.Image image = (System.Drawing.Image)row[i];
                                MemoryStream mstream = new MemoryStream();
                                image.Save(mstream, System.Drawing.Imaging.ImageFormat.Jpeg);
                                sheet.Pictures.Add(nRow, i, mstream);
                            }
                            else
                            {
                                cells[nRow, i].PutValue(row[i]);
                            }
                        }
                    }
                    catch (System.Exception e)
                    {
                        error = error + " DataTableToExcel: " + e.Message;
                    }
                }

                workbook.Save(filepath);
                return true;
            }
            catch (System.Exception e)
            {
                error = error + " DataTableToExcel: " + e.Message;
                return false;
            }
        }
        /// <summary>
        ///  
        /// </summary>
        /// <param name="file"> EXCEL </param>
        /// <param name="sheetname"> </param>
        /// <param name="toimagefile"> </param>
        public static void CellConverImge(string file, string sheetname, string toimagefile)
        {
            //Create a new Workbook object and
            //Open a template Excel file.
            Workbook book = new Workbook(file);
            //Get the first worksheet.
            Worksheet sheet = book.Worksheets[sheetname];

            //Define ImageOrPrintOptions
            ImageOrPrintOptions imgOptions = new ImageOrPrintOptions();
            //Specify the image format
            imgOptions.ImageFormat = System.Drawing.Imaging.ImageFormat.Jpeg;
            //Only one page for the whole sheet would be rendered
            imgOptions.OnePagePerSheet = true;

            //Render the sheet with respect to specified image/print options
            SheetRender sr = new SheetRender(sheet, imgOptions);
            //Render the image for the sheet
            Bitmap bitmap = sr.ToImage(0);

            //Save the image file specifying its image format.
            bitmap.Save(toimagefile);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="sURL"></param>
        /// <param name="toExcelFile"></param>
        public static void LoadUrlImage(string sURL,string toExcelFile)
        {
            //Define memory stream object
            System.IO.MemoryStream objImage;

            //Define web client object
            System.Net.WebClient objwebClient;

            //Define a string which will hold the web image url
            //string sURL = "http://files.myopera.com/Mickeyjoe_irl/albums/38458/abc.jpg";

            try
            {
                //Instantiate the web client object
                objwebClient = new System.Net.WebClient();

                //Now, extract data into memory stream downloading the image data into the array of bytes
                objImage = new System.IO.MemoryStream(objwebClient.DownloadData(sURL));

                //Create a new workbook
                Aspose.Cells.Workbook wb = new Aspose.Cells.Workbook();

                //Get the first worksheet in the book
                Aspose.Cells.Worksheet sheet = wb.Worksheets[0];

                //Get the first worksheet pictures collection
                Aspose.Cells.Drawing.PictureCollection pictures = sheet.Pictures;

                //Insert the picture from the stream to B2 cell
                pictures.Add(1, 1, objImage);

                //Save the excel file  "d:\\test\\webimagebook.xls"
                wb.Save(toExcelFile);
            }
            catch (Exception ex)
            {
                //Write the error message on the console
                Console.WriteLine(ex.Message);
            }
        }
        /// <summa


  /// <summary>
        ///  
        /// 20150228
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnFile_Click(object sender, EventArgs e)
        {
                  try
                  {
                //bool imail = false;
                this.Cursor = Cursors.WaitCursor;
                openFileDialog1.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
                //JPEG Files (*.jpeg)|*.jpeg|PNG Files (*.png)|*.png|JPG Files (*.jpg)|*.jpg|GIF Files (*.gif)|*.gif
                openFileDialog1.FileName = "";
                openFileDialog1.Filter = "Excel 2000-2003 files(*.xls)|*.xls|Excel 2007 files (*.xlsx)|*.xlsx";//|(*.xlsx)|*.xlsx Image Files(*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|All files (*.*)|*.*  txt files (*.txt)|*.txt|All files (*.*)|*.*" 
                openFileDialog1.FilterIndex = 2;
                openFileDialog1.RestoreDirectory = true;
                if (openFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    if (!openFileDialog1.FileName.Equals(String.Empty))
                    {
                        // 
                        this.combSheet.DataSource = null;
                        if (this.combSheet.Items.Count != 0)
                        {
                            this.combSheet.Items.Clear();
                        }
                        FileInfo f = new FileInfo(openFileDialog1.FileName);
                        if (f.Extension.Equals(".xls") || f.Extension.Equals(".XLS") || f.Extension.Equals(".xlsx"))
                        {
                            this.Cursor = Cursors.WaitCursor;
                            strFileUrl = openFileDialog1.SafeFileName;
                            this.txtFileUrl.Text = openFileDialog1.FileName;
                            string currentfilename = openFileDialog1.FileName;
                            this.txtFileUrl.Text = currentfilename;

                            // 
                            // ("[email protected]", "geovindu", " ", " ", currentfilename);
                            //MessageBox.Show(imail.ToString());
                            AsposeExcel.ReadExcelCombox(currentfilename,combSheet);

     

                            this.Cursor = Cursors.Default;
                        }
                        else
                        {
                            MessageBox.Show(" ");
                        }
                    }
                    else
                    {
                        MessageBox.Show(" ");
                    }


                }
            }
            catch (Exception ex)
            {
                ex.Message.ToString();
            }
                  this.Cursor = Cursors.Default;
        }
        /// <summary>
        ///  
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnImport_Click(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
             // 
             dt= AsposeExcel.ReadExcel(this.txtFileUrl.Text.Trim(), this.combSheet.Text.Trim());

             this.dataGridView1.DataSource = dt;           


        }