How can I set custom length of paper

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C#

Hey ..
In working On a POS ..
I want to print the bill on Roll paper or any type of printer ..
I am using Crystal report ..
My Question is How do I set a custom Length of paper according to the items / records present in the report at that time .. ?
Please help me ..

SqlDataAdapter da = new SqlDataAdapter("SELECT * from BillMaster where InvoiceNo ='" + inv + "'", cs);
               // SqlDataAdapter da = new SqlDataAdapter("SELECT * from BillMaster where InvoiceNo = INV-78472734", cs);
               // SqlDataAdapter da = new SqlDataAdapter("SELECT * from Sales ", cs);
               DataSet4 dr = new DataSet4();
               da.Fill(dr.View4);
               CrystalReport4 cr = new CrystalReport4();
               cr.SetDataSource(dr);
               crystalReportViewer1.ReportSource = cr;

               PrintDocument pd = new PrintDocument();
               string defaultPrinter = pd.PrinterSettings.PrinterName;

               height += (cr.Rows.Count * 5F);
              // MessageBox.Show("Test: " + height);
               PaperSize pkCustomSize1 = new PaperSize("First custom size", 4, (int)height);

               pd.DefaultPageSettings.PaperSize = pkCustomSize1;
               foreach (PaperSize paperSize in pd.PrinterSettings.PaperSizes)
               {
                   if (paperSize.PaperName == "Envelope Monarch")
                   {
                       //MessageBox.Show("Test: " + rptDocument.PrintOptions.PaperSize);
                       try
                       {
                           cr.PrintOptions.PaperSize = (CrystalDecisions.Shared.PaperSize)paperSize.RawKind;

                       }
                       catch (Exception Ex)
                       {
                           MessageBox.Show("Exception: " + Ex);
                           return;
                       }

                       //crystalReportViewer1.Refresh();

                   }
               }

               MessageBox.Show("Test: " + cr.PrintOptions.PaperSize);
               MessageBox.Show("Test: " + pd.DefaultPageSettings.PaperSize);
               // cr.PrintOptions.ApplyPageMargins(pageMargins);
               crystalReportViewer1.RefreshReport();
               crystalReportViewer1.Show();
               // cr.PrintOptions.PrinterName = "Hewlett-Packard LaserJet 4100 Series";

               //  cr.PrintToPrinter(1,false, 0, 0);
               // crystalReportViewer1.Refresh();}

What I have tried:

I read the related posts here .. But still cant understand ..