filtering excel file with asp.net

protected void FillDataSet()
    {

        try
        {
            
          
            Microsoft.Office.Interop.Excel.ApplicationClass app = new Microsoft.Office.Interop.Excel.ApplicationClass();
            Microsoft.Office.Interop.Excel.Worksheet oSheet;

            string strFilename = FileUpload.PostedFile.FileName;
            strFilename = System.IO.Path.GetFileName(strFilename);
            string ext = Path.GetExtension(strFilename);
            bool hasHeaders = true;
            string HDR = hasHeaders ? "Yes" : "No";
            string strConn;

            //check extension of file 

            if (ext.ToLower() == ".xls")
            {


                //creaate connection with excel using OLEDB
                strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fu + " ;Extended Properties=\"Excel 8.0;HDR=" + HDR + ";IMEX=1\"";

                Microsoft.Office.Interop.Excel.WorkbookClass workBook = (Microsoft.Office.Interop.Excel.WorkbookClass)app.Workbooks.Open(fu, 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
                oSheet = (Microsoft.Office.Interop.Excel.Worksheet)workBook.ActiveSheet;
                app.Visible = false;

                //You must use the $ after the object you reference in the spreadsheet

                OleDbDataAdapter myCmd = new OleDbDataAdapter("SELECT * FROM [" + oSheet.Name + "$]", strConn);


                myCmd.Fill(myDs);


                string source = @"F:\TEMP\" + strFilename;
                string target = @"F:\TEMP\temp\" + strFilename;
             

                //move file to another folder if exists
                if (File.Exists(target))
                    File.Delete(target);
                File.Move(source, target);

            }

            else if (ext.ToLower() == ".xlsx")
            {
             
                strConn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fu + ";Extended Properties=\"Excel 12.0;HDR=" + HDR + ";IMEX=2\"";

                //You must use the $ after the object you reference in the spreadsheet

                Microsoft.Office.Interop.Excel.WorkbookClass workBook = (Microsoft.Office.Interop.Excel.WorkbookClass)app.Workbooks.Open(fu, 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
                oSheet = (Microsoft.Office.Interop.Excel.Worksheet)workBook.ActiveSheet;
                app.Visible = false;

                //You must use the $ after the object you reference in the spreadsheet

                OleDbDataAdapter myCmd = new OleDbDataAdapter("SELECT * FROM [" + oSheet.Name + "$]", strConn);
                
                //fill dataset with your excel data

                myCmd.Fill(myDs);
                DataTable dtMyExcel = new DataTable();
                dtMyExcel = myDs.Tables[0];

                #region Make DataTable for Nationality

                DataTable dtCopyMyExcel = new DataTable();
                dtCopyMyExcel = dtMyExcel.Copy();
                DataView view = new DataView(dtCopyMyExcel);
                DataTable distinctValues = view.ToTable(true, "Nationality");


                DataTable dtNationality = new DataTable();
                dtNationality.Columns.Add("NationalityID", typeof(int));
                dtNationality.Columns.Add("Nationality", typeof(string));


                if (distinctValues.Rows.Count > 0)
                {
                    int slNo = 1;
                    foreach (DataRow objDr in distinctValues.Rows)
                    {
                        DataRow drNewNational = dtNationality.NewRow();
                        drNewNational["NationalityID"] = slNo.ToString();
                        drNewNational["Nationality"] = objDr["Nationality"].ToString();
                        dtNationality.Rows.Add(drNewNational);
                        slNo++;
                    }
                }

                #endregion


                #region Make Process for Employee

              

                DataTable dtEmployee= new DataTable();
                dtEmployee.Columns.Add("EmployeeId", typeof(int));
                dtEmployee.Columns.Add("EmployeeName", typeof(string));


                if (dtMyExcel.Rows.Count > 0)
                {
                   
                    foreach (DataRow objDr in dtMyExcel.Rows)
                    {
                        DataRow drdtEmployee = dtEmployee.NewRow();
                        drdtEmployee["EmployeeId"] = objDr["EmployeeId"].ToString();
                        drdtEmployee["EmployeeName"] = objDr["EmployeeName"].ToString();
                        dtEmployee.Rows.Add(drdtEmployee);
                    
                    }
                }
                #endregion



                //string source = @"F:\TEMP\" + strFilename;
                //string target = @"F:\TEMP\temp\" + strFilename;
              

                //if (File.Exists(target))
                //    File.Delete(target);
                //File.Move(source, target);
            }
            else
            {

                Response.Write("Check the extension of uploaded file.");
                            
            }
        }
        catch (Exception ex)
        {
            
            Response.Write("Error !" + ex.Message);
        }




    }