6

我一直在尝试为我正在尝试编写的 linq 查询找到合适的解决方案。

在我的模型结构中，我有一个 Item 类，它包含一个 PaymentRecords 列表。我希望我的查询实现的是：

public class PaymentRecord
{
    public int PaymentRecordId { get; set; }

    [Required]
    public double PaymentAmount { get; set; }

    [Required]
    public DateTime DateOfPayment { get; set; }

    [Required]
    public bool FinalPayment { get; set; }

    [JsonIgnore]
    public Item Item{ get; set; }
}

public class Item
{
    public int ItemId { get; set; }

    public List<PaymentRecord> PaymentRecords {get; set;}

    ...various other properties
}

选择所有项目，其中 PaymentRecord 列表与以下条件匹配（工作正常），或者 PaymentRecord 为空，例如 Items 类没有 PaymentRecord。有没有办法做到这一点？

var result = m_context.Item
            .SelectMany(
                x => x.PaymentRecords.Where(p => (p.FinalPayment == true
                                              && p.DateOfPayment >= _revenueStatementRequest.StartDate
                                              && p.DateOfPayment <= _revenueStatementRequest.EndDate)
                                              || p.FinalPayment != true),
                (x, p) => x
            )
            .ToList();

理想情况下，我想做类似下面的事情，但我无法得到任何类似的工作：

var result = m_context.Item
            .SelectMany(
                x => x.PaymentRecords.Where(p => (p.FinalPayment == true
                                              && p.DateOfPayment >= _revenueStatementRequest.StartDate
                                              && p.DateOfPayment <= _revenueStatementRequest.EndDate)
                                              || p.FinalPayment != true)
                || x.PaymentRecords == null,
                (x, p) => x
            )
            .ToList();

根据给出的答案工作后，我有这个：

 m_context.Item.Where(c => (!
                            c.PaymentRecords.Any(q => (q.FinalPayment &&
                                                            q.DateOfPayment >= _revenueStatementRequest.StartDate &&
                                                            q.DateOfPayment <= _revenueStatementRequest.EndDate)
                                                            || q.FinalPayment != true
                                                )
                            )
                    && (c..Type == Booked || c.Type == Reserved)
                    && (c.StartDate < _revenueStatementRequest.StartDate)
                    )
4

2 回答 2

1

你可以在没有SelectMany

        List<Item> res = m_context.Items
                      .Where(c => !c.PaymentRecords
                                .Any(q => (q.FinalPayment && 
                                        q.DateOfPayment >=_revenueStatementRequest.StartDate &&
                                        q.DateOfPayment <= _revenueStatementRequest.EndDate)
                                        || !q.FinalPayment)
                            )
    //**EDIT**
    .Where(c => c.StartDate < _revenueStatementRequest.StartDate)
 //this is comment out, so we can better test on the more complex part of the query
  //.Where(c => c.Type == Booked || c.Type == Reserved)   
    .ToList();

这样你得到一个List<Item>而不是List<PaymentRecord>

于 2013-03-14T14:10:52.507 回答
1

选择所有项目，其中 PaymentRecord 列表与以下条件匹配（工作正常），或者 PaymentRecord 为空，例如 Items 类没有 PaymentRecord。

var result = m_context.Item
                      .Where(x => !x.PaymentRecords.Any() ||
                                   x.PaymentRecords.Any(p => (p.FinalPayment == true
                                                        && p.DateOfPayment >= _revenueStatementRequest.StartDate
                                                        && p.DateOfPayment <= _revenueStatementRequest.EndDate)
                                                        || p.FinalPayment != true))
                      .ToList();

我看不出有什么理由在SelectMany这里使用。简单Where的条件就可以完成这项工作。

于 2013-03-14T14:11:44.197 回答