c#怎么设置打印份数，怎么弹出选择打印机

c#怎么设置打印份数，怎么弹出选择打印机；
PrintDocument pd = new PrintDocument();


            pd.PrintPage += new PrintPageEventHandler(pd_PrintPage);
            pd.PrinterSettings.Copies = 2;
            PrintPreviewDialog cppd = new PrintPreviewDialog();
            cppd.Document = pd;
            cppd.Document = pd;


            cppd.ShowDialog();代码是这样写的，打印份数无效，还是打印一份