C# 如何使用LINQ/Lambda从关系导航键中获取selectmany？

我们与实体模型有着不同的关系。我想找到下面的答案

表：客户

[Table("CustomerTable")]
public partial class CustomerTable
{
    [Key]
    public int Id { get; set; }

    [Required]
    [StringLength(50)]
    public string Name { get; set; }

    [Required]
    [StringLength(20)]
    public string Country { get; set; }


    public virtual CompanyTable CompanyTable { get; set; }

    public virtual CurrencyTable CurrencyTable { get; set; }

    public virtual LoginTable LoginTable { get; set; }

    public virtual ICollection<ProcessTable> ProcessTables { get; set; }

}

我想显示客户的记录，包括流程的剩余付款和总付款

• 公司有权创建新客户。（我们正在储存的时间 客户的总付款和首次付款，同时 将初始值存储到ProcessPaymentMapping表）

• 一个公司有多个流程

• 一个进程有多个ProcessPaymentMapping记录
• 一个客户有一个或多个由公司注册的流程
• ProcessPaymentMapping表存储了带有日期的付款历史记录
• 每次客户为运行流程付费时

流程表仅存储了公司在新流程注册时的总金额值

我想显示如下客户付款

Index | Customer Name | Process ID | Total Amount | Paid Amount | Remaining Amount 
1. | Jhon Michel  | 544545 | 150 USD | 100 USD | 50 USD
2. | Arena Bosch  | 544546 | 200 USD | 50 USD | 150 USD

像智者一样。 如何在实体中使用分组依据？

试试这个

            CompanyTable companyTable = new CompanyTable();

            var results = (from ct in companyTable.CustomerTables
                          join pt in companyTable.ProcessTables on ct.Id equals pt.CustomerId
                          select new { customerName = ct.CompanyTable.Name, processId = pt.Id, totalPayment = pt.TotalPayment, paidAmount = pt.PaymentReceived, remainingAmount = pt.TotalPayment - pt.PaymentReceived }).ToList();

---

如果您还需要索引，请使用此

            var results = (from ct in companyTable.CustomerTables
                          join pt in companyTable.ProcessTables on ct.Id equals pt.CustomerId
                          select new { customerName = ct.CompanyTable.Name, processId = pt.Id, totalPayment = pt.TotalPayment, paidAmount = pt.PaymentReceived, remainingAmount = pt.TotalPayment - pt.PaymentReceived })
                          .Select((x,i) => new { index = i, customerName = x.customerName, processId = x.processId, totalPayment = x.totalPayment,  paidAmount = x.paidAmount, remainingAmount = x.remainingAmount})
                          .ToList();

---

添加一个GroupBy。不太清楚如何处理这三个金额。猜猜看

            var results = (from ct in companyTable.CustomerTables
                          join pt in companyTable.ProcessTables on ct.Id equals pt.CustomerId
                          select new { customerName = ct.CompanyTable.Name, processId = pt.Id, totalPayment = pt.TotalPayment, paidAmount = pt.PaymentReceived, remainingAmount = pt.TotalPayment - pt.PaymentReceived })
                          .GroupBy(x => x.processId)\
                           .Select((x,i) => new { index = i, customerName = x.FirstOrDefault().customerName, processId = x.FirstOrDefault().processId, 
                               totalPayment = x.Sum(y => y.totalPayment),  paidAmount = x.Sum(y => y.paidAmount), remainingAmount = x.Sum(y => y.remainingAmount)})
                          .ToList();

---

实际上，在ProcessPaymentMapping表上需要groupby，将有多个processid条目和多个在不同日期收到的付款。。我们必须把它们加起来，然后在工艺表的总付款上加上差额，才能知道剩余金额。。

            CompanyTable companyTable = new CompanyTable();

            var results = (from ct in companyTable.CustomerTables
                          join pt in companyTable.ProcessTables on ct.Id equals pt.CustomerId
                          select new { customerName = ct.CompanyTable.Name, processId = pt.Id, totalPayment = pt.TotalPayment, paidAmount = pt.PaymentReceived, remainingAmount = pt.TotalPayment - pt.PaymentReceived }).ToList();

            var results = (from ct in companyTable.CustomerTables
                          join pt in companyTable.ProcessTables on ct.Id equals pt.CustomerId
                          select new { customerName = ct.CompanyTable.Name, processId = pt.Id, totalPayment = pt.TotalPayment, paidAmount = pt.PaymentReceived, remainingAmount = pt.TotalPayment - pt.PaymentReceived })
                          .Select((x,i) => new { index = i, customerName = x.customerName, processId = x.processId, totalPayment = x.totalPayment,  paidAmount = x.paidAmount, remainingAmount = x.remainingAmount})
                          .ToList();

            var results = (from ct in companyTable.CustomerTables
                          join pt in companyTable.ProcessTables on ct.Id equals pt.CustomerId
                          select new { customerName = ct.CompanyTable.Name, processId = pt.Id, totalPayment = pt.TotalPayment, paidAmount = pt.PaymentReceived, remainingAmount = pt.TotalPayment - pt.PaymentReceived })
                          .GroupBy(x => x.processId)\
                           .Select((x,i) => new { index = i, customerName = x.FirstOrDefault().customerName, processId = x.FirstOrDefault().processId, 
                               totalPayment = x.Sum(y => y.totalPayment),  paidAmount = x.Sum(y => y.paidAmount), remainingAmount = x.Sum(y => y.remainingAmount)})
                          .ToList();