Question

我创建了一个EF Join。 frameStart有19条记录，frameEnd有42条记录，但当我进行加入（framing）时，只有10条记录。我相信只有10条记录，因为它正在加入可以与匹配键分组的记录。代码如下。我如何做到这一点，以便当它进行连接时，我得到所有记录的列表，即使那些没有＆＃34;匹配＆＃34;？

public class s84_Report_FrameLabor
{
    public int CustomerID { get; set; }
    public string CustomerName { get; set; }
    public int SubdivisionID { get; set; }
    public string SubdivisionName { get; set; }
    public int LotNumber { get; set; }
    public string InstallManagerStart { get; set; }
    public string InstallManagerComplete { get; set; }
    public DateTime FrameLaborStart { get; set; }
    public DateTime FrameLaborComplete { get; set; }
    public int Duration { get; set; }

    /*
        Frame Labor Start    ------ Product ID: 26
        Frame Labor Complete ------ Product ID: 8
    */

    public static List<s84_Report_FrameLabor> getDurationReport()
    {
        using (var context = PrimaryConnection.returnNewConnection())
        {
            var frameStart = (from c in context.s84_Schedule
                             where c.ProductID == 26 && c.Completed == false
                             select new
                             {
                                 CustomerID = c.CustomerID,
                                 CustomerName = c.s84_Customer.CustomerName,
                                 SubdivisionID = c.SubdivisionID,
                                 SubdivisionName = c.s84_Subdivision.SubdivisionName,
                                 LotNumber = c.LotNumber,
                                 FrameLaborStart = c.CustomerExpectedDate
                             }).ToList();

            var frameEnd = (from c in context.s84_Schedule
                           where c.ProductID == 8 && c.Completed == false
                           select new
                           {
                               CustomerID = c.CustomerID,
                               SubdivisionID = c.SubdivisionID,
                               LotNumber = c.LotNumber,
                               FrameLaborComplete = c.CustomerExpectedDate
                           }).ToList();

            var framing = from c in frameStart
                          join e in frameEnd on new { c.CustomerID, c.SubdivisionID, c.LotNumber } equals new { e.CustomerID, e.SubdivisionID, e.LotNumber }
                          select new s84_Report_FrameLabor
                          {
                              CustomerID = c.CustomerID,
                              CustomerName = c.CustomerName,
                              SubdivisionID = c.SubdivisionID,
                              SubdivisionName = c.SubdivisionName,
                              LotNumber = c.LotNumber,
                              FrameLaborStart = c.FrameLaborStart,
                              FrameLaborComplete = e.FrameLaborComplete,
                              Duration = (e.FrameLaborComplete - c.FrameLaborStart).Days
                          };

            return framing.ToList();
        }
    }
}

Answer 1

感谢Andre，stuartd和James R.，我发现解决方案是使用EntityFramework DefaultIfEmpty()。

            var framing = from c in frameStart
                          join e in frameEnd on new { c.CustomerID, c.SubdivisionID, c.LotNumber } equals new { e.CustomerID, e.SubdivisionID, e.LotNumber } into jointable
                          from z in jointable.DefaultIfEmpty()
                          select new s84_Report_FrameLabor
                          {
                              CustomerID = c.CustomerID,
                              CustomerName = c.CustomerName,
                              SubdivisionID = c.SubdivisionID,
                              SubdivisionName = c.SubdivisionName,
                              LotNumber = c.LotNumber,
                              FrameLaborStart = c.FrameLaborStart,
                              FrameLaborComplete = z.FrameLaborComplete,
                              Duration = c.FrameLaborStart == null ? z.FrameLaborComplete == null ? (z.FrameLaborComplete - c.FrameLaborStart).Days : 0 : 0
                          };

            return framing.ToList();

C＃EntityFramework加入所有记录

1 个答案: