拉姆达表达式的一些备忘

1、左外连接

 

private string qtr, rpt;
private List<CommitDetail> _cdList;
private List<CommitDetailExt> _cdextList;
        private List<HddProgramCutoffLeadSetup> _hpclsList;

private void loadData(string qtr, string rpt)
        {
            using (DBConn db = new DBConn())
            {
                this._cdList = db.CommitDetail.Where(p => p.Deleted == false && p.rpt_label == this.rpt && p.QTR == this.qtr).ToList();
                this._hpclsList = db.HddProgramCutoffLeadSetup.Where(p => p.Deleted == false).ToList();
                this._ludayList = db.LU_DAY.ToList();
                this._luweekList = db.LU_WEEK.ToList();
            }

            _cdextList = this._cdList
                .SelectMany(x => this._hpclsList.Where(y => y.Capacity == x.CAPACITY && y.Program == x.NATIVE_ALT_FAMILY).DefaultIfEmpty(),
                    (x, y) => new CommitDetailExt {
                        CAPACITY = x.CAPACITY,
                        Commit_QTY = x.Commit_QTY,
                        ConcurrencyMark = x.ConcurrencyMark,
                        CreatedAt = x.CreatedAt,
                        CreatedUserId = x.CreatedUserId,
                        CUSTOMER_CODE = x.CUSTOMER_CODE,
                        Deleted = x.Deleted,
                        DEST_FAC = x.DEST_FAC,
                        FACTORY = x.FACTORY,
                        FMONTH = x.FMONTH,
                        FORM_FACTOR = x.FORM_FACTOR,
                        HEAD_COUNT = x.HEAD_COUNT,
                        LastModifiedAt = x.LastModifiedAt,
                        LastModifiedUserId = x.LastModifiedUserId,
                        LeadTime = y == null ? 7 : y.LoadingDay,
                        MTH = x.MTH,
                        NATIVE_ALT_FAMILY = x.NATIVE_ALT_FAMILY,
                        NATIVE_INV_ITEM = x.NATIVE_INV_ITEM,
                        PLATTER = x.PLATTER,
                        QTR = x.QTR,
                        RPM = x.RPM,
                        rpt_label = x.rpt_label,
                        WEEK = x.WEEK,
                        WKNUM = x.WKNUM
                    }).ToList();
}

当然，也可以用groupjoin来做，不过用SelectMany可以少敲几个代码……

2、内连接

 

private string qtr, rpt;
private List<CommitDetail> _cdList;
private List<CommitDetailExt> _cdextList;
private List<HddProgramCutoffLeadSetup> _hpclsList;
        private void loadData(string qtr, string rpt)
        {
            using (DBConn db = new DBConn())
            {
                ////
                //rpt = "R8.2.0";
                //qtr = "12-Q4";
                //  this._cdListP = db.CommitDetail.ToList();
                this._cdList = db.CommitDetail.Where(p => p.Deleted == false && p.rpt_label == this.rpt && p.QTR == this.qtr).ToList();
                // this._cdList = db.CommitDetail.Where(p => p.Deleted == false && p.rpt_label == rpt && p.QTR == qtr).ToList();
                this._hpclsList = db.HddProgramCutoffLeadSetup.Where(p => p.Deleted == false).ToList();
                this._ludayList = db.LU_DAY.ToList();
                this._luweekList = db.LU_WEEK.ToList();
            }
_cdextList = this._cdList.Join(this._hpclsList,
                    x => new { k1 = x.CAPACITY, k2 = x.NATIVE_ALT_FAMILY },
                    y => new { k1 = y.Capacity, k2 = y.Program },
                    (x, y) => new CommitDetailExt
                    {
                        CAPACITY = x.CAPACITY,
                        Commit_QTY = x.Commit_QTY,
                        ConcurrencyMark = x.ConcurrencyMark,
                        CreatedAt = x.CreatedAt,
                        CreatedUserId = x.CreatedUserId,
                        CUSTOMER_CODE = x.CUSTOMER_CODE,
                        Deleted = x.Deleted,
                        DEST_FAC = x.DEST_FAC,
                        FACTORY = x.FACTORY,
                        FMONTH = x.FMONTH,
                        FORM_FACTOR = x.FORM_FACTOR,
                        HEAD_COUNT = x.HEAD_COUNT,
                        LastModifiedAt = x.LastModifiedAt,
                        LastModifiedUserId = x.LastModifiedUserId,
                        LeadTime = y.LoadingDay,
                        MTH = x.MTH,
                        NATIVE_ALT_FAMILY = x.NATIVE_ALT_FAMILY,
                        NATIVE_INV_ITEM = x.NATIVE_INV_ITEM,
                        PLATTER = x.PLATTER,
                        QTR = x.QTR,
                        RPM = x.RPM,
                        rpt_label = x.rpt_label,
                        WEEK = x.WEEK,
                        WKNUM = x.WKNUM
                    }).ToList();
}

3、groupby分组

囧……没怎么遇到复杂的。大部分都是诸如此类……

            var cdgropList = this._cdextList.GroupBy(p =>
                new
                {
                    PROGRAM = p.NATIVE_ALT_FAMILY,
                    CAPACITY = p.CAPACITY,
                    //FACTORY = p.FACTORY,                    
                    PART_NO = p.NATIVE_INV_ITEM
                });