打印帮助类

 /// <summary>
    /// 打印帮助类
    /// </summary>
    public class PrintHelper
    {  private int m_currentPageIndex;
        private IList<Stream> m_streams;

        /// <summary>
        /// 报表直接打印
        /// </summary>
        /// <param name="reportPath">报表文件路径</param>
        /// <param name="printerName">打印机名称</param>
        /// <param name="dt">DataTable</param>
        /// <param name="sourceName">rdlc的数据集名称</param>
        /// <param name="paraList">参数列表</param>
        public void Run(string reportPath, string printerName, DataTable dt, string sourceName, List<ReportParameter> paraList)
        {
            LocalReport report = new LocalReport();
            report.ReportPath = reportPath;
            report.DataSources.Add(new ReportDataSource(sourceName,dt));
            report.EnableExternalImages = true;
            report.SetParameters(paraList);
            Export(report);
            m_currentPageIndex = 0;
            Print(printerName);
        }

        private void Export(LocalReport report)
        {
            string deviceInfo =
                "<DeviceInfo>" + 
                " <OutputFormat>EMF</OutputFormat>"+
                "</DeviceInfo>";
            Warning[] warnings;
            m_streams = new List<Stream>();
            try
            {
                report.Render("Image", deviceInfo, CreateStream, out warnings);
            }
            catch (Exception ex)
            {
                Exception innerEx = ex.InnerException;
                while (innerEx != null)
                {
                    string errmessage = innerEx.Message;
                    innerEx = innerEx.InnerException;

                }
            }

            foreach (Stream stream in m_streams)
            {
                stream.Position = 0;
            }
        }

        private Stream CreateStream(string name, string fileNameExtension, Encoding encoding, string mimeType, bool willSeek)
        {
            Stream stream = new FileStream(name + DateTime.Now.Millisecond + "." + fileNameExtension, FileMode.Create);
            m_streams.Add(stream);
            return stream;
        }
        private void Print(string printerName)
        {
            if (m_streams == null || m_streams.Count == 0) return;
            PrintDocument printDoc = new PrintDocument();
            if (printerName.Length > 0)
            {
                printDoc.PrinterSettings.PrinterName = printerName;
            }
            foreach (PaperSize ps in printDoc.PrinterSettings.PaperSizes)
            {
                if (ps.PaperName == "A4")
                {
                    printDoc.PrinterSettings.DefaultPageSettings.PaperSize = ps;
                    printDoc.DefaultPageSettings.PaperSize = ps;
                }
            }
            if (!printDoc.PrinterSettings.IsValid)
            {
                string msg = string.Format("找不到打印机：{0}",printerName);
                LogUtil.Log(msg);
                return;
            }
            printDoc.PrintPage += new PrintPageEventHandler(PrintPage);
            printDoc.Print();
        }

        private void PrintPage(object sender, PrintPageEventArgs ev)
        {
            Metafile pageImage = new Metafile(m_streams[m_currentPageIndex]);
            ev.Graphics.DrawImage(pageImage, 0, 0, 827, 1169);//像素
            m_currentPageIndex++;
            ev.HasMorePages = (m_currentPageIndex < m_streams.Count);
        }
    }

string deviceInfo =
            "<DeviceInfo>" +
            "  <OutputFormat>EMF</OutputFormat>" +
            "  <PageWidth>210mm</PageWidth>" +
            "  <PageHeight>297mm</PageHeight>" +
            "  <MarginTop>5mm</MarginTop>" +
            "  <MarginLeft>10mm</MarginLeft>" +
            "  <MarginRight>10mm</MarginRight>" +
            "  <MarginBottom>5mm</MarginBottom>" +
            "</DeviceInfo>";//这里是设置打印的格式 边距什么的