Question

我向PassAllocations类添加了以下属性：

[NotMapped]
public int PendingForApprovalCount { get; set; }

 var passAllocations = db.PassAllocations.Include(p => p.PassRule)
.Where(p => p.CompanyID == company.CompanyID).ToList();

我试图用PendingForApprovalCount的结果填充passAllocations列表中的每个db.PassLinkings.Where(p => p.PassAllocationID == parentid and p.status="Pending").ToList()属性

在每个PassAllocationID列表中，{parent}是passAllocations

Answer 1

passAllocations
.ForEach(x=>x.PendingForApprovalCount=db.PassLinkings
                                        .Where(p => p.PassAllocationID == x.id &&
                                                    p.status="Pending")
                                        .Count())

这可能会为您提供正确的结果，但这不是一个明智的解决方案，因为它会导致对db的多次点击，最终会影响性能。

var desiredResult=(from a in db.PassAllocations
                               .Include(pa => pa.PassRule)
                               .Where(pa => pa.CompanyID == company.CompanyID)
                   join b in db.PassLinkings
                               .Where(pl => pl.status="Pending")
                               .GroupBy(pl=>pl.PassAllocationID)
                   on a.PassAllocationID equals b.Key
                   select new {a,b})
                  .Select(x=>new PassAllocation
                             {
                              PassAllocationID=x.a.PassAllocationID,
                              .
                              .  
                              .   <------------Other Properties
                              .
                              .
                              PendingForApprovalCount=x.b.Count()
                              }).ToList();

希望有帮助。

如何在Linq中使用计数填充NotMapped属性？

1 个答案: