Đa luồng công nợ

private object objLock = new object();

        private bool isStop = false;

        private int _taskIndex;

        private List<BackgroundWorker> Threads = new List<BackgroundWorker>();

        private List<CongNoItem>

            _noDauKy,

            _phatSinh,

            _daThu,

            _khauTru,

            _thuTruocA,

            _thuTruocB,

            _conNo;

        private System.Collections.Generic.List<Library.mbMatBang> _lMatBang;

        private System.Collections.Generic.List<Library.tnKhachHang> _lKhachHang;

        public frmReceivables()

        {

            InitializeComponent();

            for (int i = 0; i <= 8; i++)

            {

                var thread = new BackgroundWorker();

                thread.DoWork += thread_DoWork;

                thread.RunWorkerCompleted += thread_RunWorkerCompleted;

                Threads.Add(thread);

            }

        }

        private void thread_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

        {

            if (isStop)

            {

                if (!Threads.Any(_ => _.IsBusy))

                    GetData();

            }

            else ((BackgroundWorker) sender).RunWorkerAsync();

        }

        private void thread_DoWork(object sender, DoWorkEventArgs e)

        {

            GetTask();

        }

        public class CongNoItem

        {

            public int? MaKH { get; set; }

            public decimal? SoTien { get; set; }

        }

        private void GetData()

        {

            var wai = DialogBox.WaitingForm();

            wai.Show();

            gcHoaDon.DataSource = (from kh in _lKhachHang

                join mb in _lMatBang on kh.MaKH equals mb.MaKHF1

                join ndk in _noDauKy on kh.MaKH equals ndk.MaKH into noDauKy

                from ndk in noDauKy.DefaultIfEmpty()

                join ps in _phatSinh on kh.MaKH equals ps.MaKH into phatSinh

                from ps in phatSinh.DefaultIfEmpty()

                join dt in _daThu on kh.MaKH equals dt.MaKH into daThu

                from dt in daThu.DefaultIfEmpty()

                join kt in _khauTru on kh.MaKH equals kt.MaKH into khauTru

                from kt in khauTru.DefaultIfEmpty()

                join ttA in _thuTruocA on kh.MaKH equals ttA.MaKH into thuTruocA

                from ttA in thuTruocA.DefaultIfEmpty()

                join ttB in _thuTruocB on kh.MaKH equals ttB.MaKH into thuTruocB

                from ttB in thuTruocA.DefaultIfEmpty()

                join cn in _conNo on kh.MaKH equals cn.MaKH into conNo

                from cn in conNo.DefaultIfEmpty()

                select new

                {

                    kh.MaKH, kh.KyHieu, kh.MaPhu, TenKH = kh.IsCaNhan == true ? kh.HoKH + " " + kh.TenKH : kh.CtyTen,

                    DienThoai = kh.DienThoaiKH, kh.EmailKH, DiaChi = kh.CtyDiaChi, LoaiMB = mb.mbLoaiMatBang.TenLMB,

                    mb.MaMB, NoDauKy = ndk != null ? ndk.SoTien : 0,

                    PhatSinh = ps != null ? ps.SoTien : 0, DaThu = dt != null ? dt.SoTien : 0,

                    KhauTru = kt != null ? kt.SoTien : 0, ConNo = cn != null ? cn.SoTien : 0,

                    ThuTruoc = (ttA != null ? ttA.SoTien : 0) - (ttB != null ? ttB.SoTien : 0)

                }).ToList();

            itemNap.Visibility = DevExpress.XtraBars.BarItemVisibility.Always;

            wai.Dispose();

        }

        private void GetTask()

        {

            Library.MasterDataContext db = new Library.MasterDataContext();

            var maTn = (byte) itemToaNha.EditValue;

            var thang = System.Convert.ToInt32(itemThang.EditValue);

            var nam = System.Convert.ToInt32(itemNam.EditValue);

            var tuNgay = new System.DateTime(nam, thang, 1);

            var denNgay = Library.Common.GetLastDayOfMonth(thang, nam);

            var ngayHienTai = System.DateTime.UtcNow.AddHours(7);

            var index = 0;

            lock (objLock) index = _taskIndex++;

            switch (index)

            {

                case 1:

                    _noDauKy = (from p in db.dvHoaDons

                        where SqlMethods.DateDiffDay(p.NgayTT, tuNgay) > 0 & p.IsDuyet == true & p.MaTN == maTn

                        group new {p} by new {p.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH,

                            SoTien = g.Sum(_ => _.p.PhaiThu -

                                (from ct in db.ptChiTietPhieuThus

                                    where ct.TableName == "dvHoaDon" & ct.LinkID == _.p.ID &

                                          SqlMethods.DateDiffDay(ct.ptPhieuThu.NgayThu,

                                              maTn == 27 ? ngayHienTai : tuNgay) >

                                          0

                                    select ct.SoTien).Sum().GetValueOrDefault() - (from ct in db.ktttChiTiets

                                    where ct.TableName == "dvHoaDon" & ct.LinkID == _.p.ID &

                                          SqlMethods.DateDiffDay(ct.ktttKhauTruThuTruoc.NgayCT,

                                              maTn == 27 ? ngayHienTai : tuNgay) > 0

                                    select ct.SoTien).Sum().GetValueOrDefault()).GetValueOrDefault()

                        }).ToList();

                    break;

                case 2:

                    _phatSinh = (from p in db.dvHoaDons

                        where SqlMethods.DateDiffMonth(p.NgayTT, tuNgay) == 0 & p.IsDuyet == true & p.MaTN == maTn

                        group new {p} by new {p.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH, SoTien = g.Sum(_ => _.p.PhaiThu).GetValueOrDefault()

                        }).ToList();

                    break;

                case 3:

                    _daThu = (from p in db.ptChiTietPhieuThus

                        join hd in db.dvHoaDons on new {p.TableName, p.LinkID} equals

                            new {TableName = "dvHoaDon", LinkID = (long?) hd.ID}

                        where SqlMethods.DateDiffMonth(p.ptPhieuThu.NgayThu, tuNgay) == 0 & hd.MaTN == maTn

                        group new {hd, p} by new {hd.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH, SoTien = g.Sum(_ => _.p.SoTien).GetValueOrDefault()

                        }).ToList();

                    break;

                case 4:

                    _khauTru = (from p in db.ktttChiTiets

                        join hd in db.dvHoaDons on new {p.TableName, p.LinkID} equals

                            new {TableName = "dvHoaDon", LinkID = (long?) hd.ID}

                        where SqlMethods.DateDiffMonth(p.ktttKhauTruThuTruoc.NgayCT, tuNgay) == 0 & hd.MaTN == maTn

                        group new {hd, p} by new {hd.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH, SoTien = g.Sum(_ => _.p.SoTien).GetValueOrDefault()

                        }).ToList();

                    break;

                case 5:

                    _thuTruocA = (from p in db.ptPhieuThus

                        where p.MaPL == 2 & SqlMethods.DateDiffDay(p.NgayThu, denNgay) >= 0 & p.MaTN == maTn

                        group new {p} by new {p.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH,

                            SoTien = g.Sum(_ => _.p.SoTien).GetValueOrDefault()

                        }).ToList();

                    break;

                case 6:

                    _thuTruocB = (from p in db.ktttKhauTruThuTruocs

                        where SqlMethods.DateDiffDay(p.NgayCT, denNgay) >= 0

                        group new {p} by new {p.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH,

                            SoTien = g.Sum(_ => _.p.SoTien).GetValueOrDefault()

                        }).ToList();

                    break;

                case 7: _lMatBang = db.mbMatBangs.Where(_ => _.MaTN == maTn).ToList();

                    break;

                case 8:

                    _lKhachHang = db.tnKhachHangs.Where(_ => _.MaTN == maTn).ToList();

                    break;

                case 9:

                    _conNo = (from p in db.dvHoaDons

                        where SqlMethods.DateDiffDay(p.NgayTT, denNgay) >= 0 & p.IsDuyet == true & p.MaTN == maTn

                        group new {p} by new {p.MaKH}

                        into g

                        select new CongNoItem

                        {

                            MaKH = g.Key.MaKH,

                            SoTien = g.Sum(_ =>

                                _.p.PhaiThu - (from ct in db.ptChiTietPhieuThus

                                                where ct.TableName == "dvHoaDon" & ct.LinkID == _.p.ID &

                                                      SqlMethods.DateDiffDay(ct.ptPhieuThu.NgayThu, denNgay) >= 0

                                                select ct.SoTien).Sum().GetValueOrDefault()

                                            - (from ct in db.ktttChiTiets

                                                where ct.TableName == "dvHoaDon" & ct.LinkID == _.p.ID &

                                                      SqlMethods.DateDiffDay(ct.ktttKhauTruThuTruoc.NgayCT, denNgay) >=

                                                      0

                                                select ct.SoTien).Sum().GetValueOrDefault()).GetValueOrDefault()

                        }).ToList();

                    break;

                default:

                    isStop = true;

                    break;

            }

        }

        private void LoadData()

        {

            _taskIndex = 1;

            isStop = false;

            gcHoaDon.DataSource = null;

            itemNap.Visibility = DevExpress.XtraBars.BarItemVisibility.Never;

            foreach (var thread in Threads)

                thread.RunWorkerAsync();

        }