Import Excel Data to DataSet of ASP.NET

protected void btnUpload_Click(object sender, EventArgs e)
{
    if(UploadfileUpload.HasFile)
    {
        string extension = Path.GetExtension(this.UploadfileUpload.FileName);
        if(extension == ".xls" || extension == ".xlsx")
        {
            string filename = Path.GetFileName(UploadfileUpload.FileName);
            filename = lblUserId.Text + filename;
            string savePath = ConfigurationSettings.AppSettings["UploadExcel"].ToString();
            bool pathExists = CheckDirectory(savePath);
            if(pathExists.Equals(true))
            {#
                region Extract Data from Excel
                string filePath = savePath + "\\" + filename;
                UploadfileUpload.PostedFile.SaveAs(filePath);
                FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read);
                IExcelDataReader excelReader;
                if(extension == ".xls") excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
                else excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
                excelReader.IsFirstRowAsColumnNames = true;#
                endregion
                DataSet ds = new DataSet();
                ds = excelReader.AsDataSet(); // From Excel Data Store in DataSet.
            }
        }
        else
        {
            lblError.Visible = true;
            lblError.Text = "File input is not correct, please upload excel files only.";
        }
    }
    else
    {
        lblError.Visible = true;
        lblError.Text = "Please upload excel files.";
    }
}