private void AsyncExcel2Pdf(string strXlsPath) { //Interlocked.Increment(ref m_ThreadCount); Excel2Pdf xls2Pdf = new Excel2Pdf(); xls2Pdf.FilePathExcel = strXlsPath; m_DeConvert[1] = xls2Pdf.ToPdf; IAsyncResult ar = m_DeConvert[1].BeginInvoke(new AsyncCallback(callbackExcel2PdfConvert), m_DeConvert[1]); //ThreadPool.QueueUserWorkItem(new WaitCallback(callbackExcel2PdfConvert), m_DeConvert[1]); }