我有三張桌子Customer，Loan和LoanHistories。Customertable 與Loantable 以一對多關系相關，并且Loantable 也以LoanHistories一對多關系相關。
以下是這些表的 C# 類：
public class Customer
{
[DatabaseGenerated(DatabaseGeneratedOption.None)]
[Display(Name = "ID NO")]
public int CustomerID { get; set; }
[Display(Name = "First Name")]
public string FirstName { get; set; }
[Display(Name = "Last Name")]
public string LastName { get; set; }
[Display(Name = "Phone Number")]
public string PhoneNo { get; set; }
[Display(Name = "Nearest Primary School")]
public string NearestPrimarySchool { get; set; }
[Display(Name = "Photo")]
public string Photo { get; set; }
public ICollection<Loan> loans { get; set; }
// public IEnumerable<LoansHistories> loansHistories { get; set; }
// public ICollection<WorkForLiving> workForLivings { get; set; }
// public ICollection<CustomersCharacterBehavior> customersCharacterBehaviors { get; set; }
}
public class Loan
{
[Key]
public int LoanID { get; set; }
[DataType(DataType.Currency)]
[Column(TypeName = "money")]
public decimal LoanAmount { get; set; }
[NotMapped]
public decimal TotalRepaidIn { get; set; }
[NotMapped]
public decimal Balance { get; set; }
[DataType(DataType.Currency)]
[Column(TypeName = "money")]
[Display(Name = "Loan Balance")]
private decimal _LoanBalance;
public decimal LoanBalance
{
get { return LoanAmount * interestRate; }
set { _LoanBalance = value; }
}
[Display(Name = "Interest Rate")]
public decimal interestRate { get; set; }
[DataType(DataType.Date)]
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
[Display(Name = "Application Date")]
public DateTime ApplicationDate { get; set; }
[DataType(DataType.Date)]
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
[Display(Name = "Disbursement Date")]
public DateTime DisbursmentDate { get; set; }
[DataType(DataType.Date)]
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
[Display(Name = "Due Date")]
public DateTime DueDate { get; set; }
[Display(Name = "Defaulted")]
public bool Defaulted { get; set; }
[Display(Name = "Approved")]
public bool Approved { get; set; }
//Navigation property
public int CustomerID { get; set; }
public Customer customer { get; set; }
//public ICollection<LoanComments> loancomments { get; set; }
public ICollection<LoansHistories> loansHistories { get; set; }
}
public class LoansHistories
{
[Key]
public int HistID { get; set; }
[DataType(DataType.Currency)]
[Column(TypeName = "money")]
[Display(Name = "Repaid Amount")]
public decimal RePaidIn { get; set; }
[DataType(DataType.Date)]
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
[Display(Name = "Repayement Date")]
public DateTime RepayementDateDate { get; set; }
[Display(Name = "No of paying interest only")]
public int NoOfPayinyingIntrestOnly { get; set; }
// Navigation properties
public int LoanID { get; set; }
public Loan loan { get; set; }
// Navigation property
// public int CustomerID { get; set; }
// public Customer customer { get; set; }
}
這是從和表LoansController中加載資料的：LoansLoansHistories
[HttpGet]
public async Task<ActionResult<IEnumerable<Loan>>> Getloans()
{
var data = await _context.loans
.Include(lh => lh.loansHistories)
.Select(l => new Loan()
{
TotalRepaidIn = l.loansHistories.Select(lh => lh.RePaidIn).Sum(),
Balance = l.loansHistories.Select(lh => lh.RePaidIn).Sum()-l.LoanAmount,
loansHistories = l.loansHistories,
ApplicationDate = l.ApplicationDate,
Defaulted = l.Defaulted,
DisbursmentDate = l.DisbursmentDate,
DueDate = l.DueDate,
LoanID = l.LoanID,
Approved = l.Approved,
interestRate = l.interestRate,
LoanAmount = l.LoanAmount
}).ToListAsync();
return data;
}
這是 JSON 格式的資料：
[
{
"loanID":1,
"loanAmount":1000.0000,
"totalRepaidIn":202700.0000,
"balance":201700.0000,
"loanBalance":15000.000000,
"interestRate":15.00,
"applicationDate":"2022-03-28T00:00:00",
"disbursmentDate":"2022-03-28T00:00:00",
"dueDate":"2022-04-28T00:00:00",
"defaulted":false,
"approved":true,
"customerID":0,
"customer":null,
"loansHistories":[
{
"histID":1,
"rePaidIn":500.0000,
"repayementDateDate":"2022-03-28T00:00:00",
"noOfPayinyingIntrestOnly":1,
"loanID":1,
"loan":null
}
]
}
]
我想從客戶控制器加載資料，但我發現物體 TotalRepaidIn 為零，我怎樣才能讓它回傳一個值，讓它在貸款控制器中回傳？沒有物體 totalRepaidIn":0.0
客戶控制器：
// GET: api/CustomersApi
[HttpGet]
public async Task<ActionResult<IEnumerable<Customer>>> Getcustomers()
{
return await _context.customers.Include(l=>l.loans).ThenInclude(h=>h.loansHistories).ToListAsync();
}
它回傳以下 Json 資料：
[
{
"customerID":30290122,
"firstName":"Isaac",
"lastName":"Kiplagat",
"phoneNo":"0724797768",
"nearestPrimarySchool":"Mokwo",
"photo":"photo",
"loans":[
{
"loanID":1,
"loanAmount":1000.0000,
"totalRepaidIn":0.0,
"balance":0.0,
"loanBalance":15000.000000,
"interestRate":15.00,
"applicationDate":"2022-03-28T00:00:00",
"disbursmentDate":"2022-03-28T00:00:00",
"dueDate":"2022-04-28T00:00:00",
"defaulted":false,
"approved":true,
"customerID":30290122,
"loansHistories":[
{
"histID":1,
"rePaidIn":500.0000,
"repayementDateDate":"2022-03-28T00:00:00",
"noOfPayinyingIntrestOnly":1,
"loanID":1
}
]
}
]
}
]
uj5u.com熱心網友回復：
一種方法就像以前一樣，您可以選擇新的 Customer 實體并為其設定值。
另一種更簡單的方法是，您可以將屬性更改為以下來計算RePaidIn：
using System.Linq; //import this namespace...
public class Loan
{
[Key]
public int LoanID { get; set; }
[DataType(DataType.Currency)]
[Column(TypeName = "money")]
public decimal LoanAmount { get; set; }
private decimal _TotalRepaidIn;
[NotMapped]
public decimal TotalRepaidIn
{
get { return loansHistories.Sum(sum => sum.RePaidIn); }
set { _TotalRepaidIn = value; }
}
//other properties
public ICollection<LoansHistories> loansHistories { get; set; } = new List<LoansHistories>();
}
在您的 中LoansController，您可以將操作改進為以下內容：
var data = await _context.loans.Include(lh => lh.loansHistories).ToListAsync();
客戶控制器也可以獲得正確的值TotalRepaidIn。
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標籤：林克 实体框架核心 asp.net-core-webapi
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