How to handle printing large number of barcode label

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C#

printing

DevExpress

hi,
i search for the best way to print barcode label (designed with XtraReport) multi-times.
ex-
if i have purchases invoice that contains this items.

----- code ---- name  ---- Quantity -----
----- 1234 ---- item1 ---- 5        -----
----- 1235 ---- item2 ---- 2        -----
----- 1236 ---- item3 ---- 4        -----

First Question:
what is the best Solution to print the 3 items every one as its Quantity (total 11 label).
Second Question:
How to Print Dual Barcode Style (Every two Labels have no space between them. )

What I have tried:

i tried ...
1- i created a List contains the Barcode Data

List<CLSBarcode> list = new List<CLSBarcode>();

where CLSBarcode is a class contains the barcode proprties.
then i created a loop to add the (11 Label) to the List

foreach (var item in InvoiceItems)
            {
                int itemID = item.stitems_ID.Value;

                var items = db01.view_items_barcode.Where(u => u.stitems_ID == itemID).Select(s => new CLSBarcode
                {
                    company_name = BasicVars.CompanyName,
                    mobile1 = BasicVars.BrMobile1,
                    mobile2 = BasicVars.BrMobile2,
                    mobile3 = BasicVars.BrMobile3,
                    adrress = BasicVars.BrAdrress,
                    country = BasicVars.BrCountry,
                    city = BasicVars.BrCity,
                    Email = BasicVars.Email,
                    stitems_ID = s.stitems_ID,
                    stitems_Status = s.stitems_Status,
                    stitems_Name = s.stitems_Name,
                    stitems_Code = s.stitems_Code,
                    catID = s.stcate_ID,
                    cat_name = s.stcate_Name,
                    unitID = s.stitemsu_ID,
                    salesprice = DbFunctions.Truncate(s.stitemsu_SalesPrice, BasicVars.CurrencyPart),
                    salespriceST = DbFunctions.Truncate(s.stitemsu_SalesPrice, BasicVars.CurrencyPart).ToString(),
                    salesdiscount = DbFunctions.Truncate(s.stitemsu_SalesDiscount, BasicVars.CurrencyPart)
                }).FirstOrDefault();

                for (int i = 0; i < item.unitQntity ; i++)
                {
                    list.Add(items);
                }
            }

then i set the report data source to this list and printed it.

report.DataSource = list;

this way work good with the small quantity. but many users says that with the large quantity it hang and the printer lamp show error (with no error msg).