NET Core 6 使用 DTO 更新数据库记录时遇到问题
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【中文标题】NET Core 6 使用 DTO 更新数据库记录时遇到问题【英文标题】：NET Core 6 Trouble updating a DB record using a DTO 【发布时间】：2022-01-12 19:03:35 【问题描述】：这是我第一次使用 DTO 将数据传输到数据库。我有这个使用 DTO 的 Create 方法（我不会显示该 DTO，因为这只是一个示例）并且工作正常：
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create(CreateDTO dto)
DropDowns();
dto.Date_Added = DateTime.Now;
try
_context.Add(dto.ToWC_Inbox());
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
catch (Exception ex)
System.Diagnostics.Debug.WriteLine("It didn't work.");
System.Diagnostics.Debug.WriteLine(ex);
return View(dto.ToWC_Inbox());
创建 DTO 缺少一些在初始创建后需要输入的字段，因此我有一个单独的用于编辑的 DTO，如下所示：
public class ReviewDTO
public int ID get; set;
[MaxLength(50)]
public string First_Name get; set; = null!;
[MaxLength(50)]
public string Last_Name get; set; = null!;
[MaxLength(10)]
public string? Gender get; set;
[MaxLength(30)]
public string? Marital_Status get; set;
[MaxLength(4)]
public string? SSN get; set;
public DateTime? DOB get; set;
[MaxLength(100)]
public string? Address get; set;
[MaxLength(12)]
public string? Phone_Number get; set;
[MaxLength(4)]
public string Org_Number get; set; = null!;
public DateTime Hire_Date get; set;
[MaxLength(20)]
public string Job_Title get; set; = null!;
[MaxLength(50)]
public string Work_Schedule get; set; = null!;
public DateTime Injury_Date get; set;
[MaxLength(10)]
public string Injury_Time get; set; = null!;
[MaxLength(15)]
public string DOT_12 get; set; = null!;
[MaxLength(10)]
public string Start_Time get; set; = null!;
[MaxLength(30)]
public string Injured_Body_Part get; set; = null!;
[MaxLength(10)]
public string? Side get; set;
public bool Missing_Work get; set;
public DateTime? Missing_Work_Date get; set;
public DateTime? Begin_Missing_Date get; set;
[MaxLength(10)]
public string? Begin_Missing_Time get; set;
public DateTime? Return_To_Work_Date get; set;
public bool Doctors_Release get; set;
public bool? Treatment get; set;
[RequiredIf("Treatment == true", ErrorMessage = "Treatment Date is required.")]
public DateTime? Treatment_Date get; set;
[MaxLength(100)]
[RequiredIf("Treatment == true", ErrorMessage = "Treatment Provider is required.")]
public string? Treatment_Provider get; set;
[MaxLength(15)]
[RequiredIf("Treatment == true", ErrorMessage = "Treatment Provider Phone is required.")]
public string? Treatment_Provider_Phone get; set;
[MaxLength(50)]
[RequiredIf("Treatment == true", ErrorMessage = "Where first treated is required.")]
public string? Transport_First_Treatment get; set;
[MaxLength(50)]
[RequiredIf("Treatment == true", ErrorMessage = "The city of treatment is required.")]
public string? Transport_City get; set;
[MaxLength(250)]
public string Injury_Description get; set; = null!;
[MaxLength(250)]
public string? Equipment get; set;
[MaxLength(50)]
public string? Witness get; set;
[MaxLength(50)]
public string? Supervisor_Name get; set;
[MaxLength(15)]
public string? Supervisor_Phone get; set;
[MaxLength(250)]
public string? Questioned get; set;
[MaxLength(250)]
public string? Medical_History get; set;
public bool Inbox_Submitted get; set;
[RequiredIf("Inbox_Submitted == false", ErrorMessage = "The reason is required.")]
public string? Inbox_Reason get; set;
[MaxLength(250)]
public string? Comments get; set;
[MaxLength(254)]
public string User_Email get; set; = null!;
[MaxLength(254)]
public string Supervisor_Email get; set; = null!;
[MaxLength(254)]
public string Safety_Specialist_Email get; set; = null!;
[MaxLength(254)]
public string? Optional_Email get; set;
[MaxLength(254)]
public string? Optional_Email2 get; set;
[MaxLength(254)]
public string? Optional_Email3 get; set;
[MaxLength(254)]
public string? HDHR_Manager_Email get; set;
public int TX_EROI_Lag get; set;
public string? Claim_Ruling get; set;
public string? Injury_Type get; set;
public DateTime? TTD_Onset_Date get; set;
public DateTime? Restricted_RTW_Date get; set;
public DateTime? Full_Duty_RTW_Date get; set;
public bool Receiving_TTD get; set;
public DateTime? Date_TTD_Award_Notice get; set;
public DateTime? Claim_Ruling_Date get; set;
public DateTime? Med_Excuse_To get; set;
public string? Doctor get; set;
public DateTime? RTW_Email_Encova get; set;
public DateTime? Lost_Time_Start1 get; set;
public DateTime? Lost_Time_End1 get; set;
public DateTime? Lost_Time_Start2 get; set;
public DateTime? Lost_Time_End2 get; set;
public DateTime? Lost_Time_Start3 get; set;
public DateTime? Lost_Time_End3 get; set;
public string? Status get; set;
public string? HR_Comments get; set;
public string Add_User get; set; = null!;
public DateTime Date_Added get; set;
public string? HR_User get; set;
public DateTime? Date_Modified get; set;
public WC_Inbox ToCompletedWC_Inbox()
return new WC_Inbox
First_Name = this.First_Name,
Last_Name = this.Last_Name,
Gender = this.Gender,
Marital_Status = this.Marital_Status,
SSN = this.SSN,
DOB = this.DOB,
Address = this.Address,
Phone_Number = this.Phone_Number,
Org_Number = this.Org_Number,
Hire_Date = this.Hire_Date,
Job_Title = this.Job_Title,
Work_Schedule = this.Work_Schedule,
Injury_Date = this.Injury_Date,
Injury_Time = this.Injury_Time,
DOT_12 = this.DOT_12,
Start_Time = this.Start_Time,
Injured_Body_Part = this.Injured_Body_Part,
Side = this.Side,
Missing_Work = this.Missing_Work,
Missing_Work_Date = this.Missing_Work_Date,
Begin_Missing_Date = this.Begin_Missing_Date,
Begin_Missing_Time = this.Begin_Missing_Time,
Return_To_Work_Date = this.Return_To_Work_Date,
Doctors_Release = this.Doctors_Release,
Treatment = this.Treatment,
Treatment_Date = this.Treatment_Date,
Treatment_Provider = this.Treatment_Provider,
Treatment_Provider_Phone = this.Treatment_Provider_Phone,
Transport_First_Treatment = this.Transport_First_Treatment,
Transport_City = this.Transport_City,
Injury_Description = this.Injury_Description,
Equipment = this.Equipment,
Witness = this.Witness,
Supervisor_Name = this.Supervisor_Name,
Supervisor_Phone = this.Supervisor_Phone,
Questioned = this.Questioned,
Medical_History = this.Medical_History,
Inbox_Submitted = this.Inbox_Submitted,
Inbox_Reason = this.Inbox_Reason,
Comments = this.Comments,
User_Email = this.User_Email,
Supervisor_Email = this.Supervisor_Email,
Safety_Specialist_Email = this.Safety_Specialist_Email,
Optional_Email = this.Optional_Email,
Optional_Email2 = this.Optional_Email2,
Optional_Email3 = this.Optional_Email3,
HDHR_Manager_Email = this.HDHR_Manager_Email,
TX_EROI_Lag = this.TX_EROI_Lag,
Claim_Ruling = this.Claim_Ruling,
Injury_Type = this.Injury_Type,
TTD_Onset_Date = this.TTD_Onset_Date,
Restricted_RTW_Date = this.Restricted_RTW_Date,
Full_Duty_RTW_Date = this.Full_Duty_RTW_Date,
Receiving_TTD = this.Receiving_TTD,
Date_TTD_Award_Notice = this.Date_TTD_Award_Notice,
Claim_Ruling_Date = this.Claim_Ruling_Date,
Med_Excuse_To = this.Med_Excuse_To,
Doctor = this.Doctor,
RTW_Email_Encova = this.RTW_Email_Encova,
Lost_Time_Start1 = this.Lost_Time_Start1,
Lost_Time_End1 = this.Lost_Time_End1,
Lost_Time_Start2 = this.Lost_Time_Start2,
Lost_Time_End2 = this.Lost_Time_End2,
Lost_Time_Start3 = this.Lost_Time_Start3,
Lost_Time_End3 = this.Lost_Time_End3,
Add_User = this.Add_User,
Date_Added = this.Date_Added,
HR_User = this.HR_User,
Date_Modified = this.Date_Modified,
;
以及控制器方法：
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(int id, ReviewDTO dto)
System.Diagnostics.Debug.WriteLine("ID: " + id);
System.Diagnostics.Debug.WriteLine("DTO ID: " + dto.ID);
DropDowns();
if (id != dto.ID)
return NotFound();
try
System.Diagnostics.Debug.WriteLine("Updating DB");
System.Diagnostics.Debug.WriteLine("ID again: " + id);
System.Diagnostics.Debug.WriteLine("DTO ID again: " + dto.ID);
_context.Update(dto.ToCompletedWC_Inbox());
await _context.SaveChangesAsync();
catch (DbUpdateConcurrencyException)
if (!WC_InboxExists(id))
return NotFound();
else
throw;
return RedirectToAction(nameof(Index));
问题在于，Edit 方法不是更新现有记录，而是使用更新后的信息创建一个全新的记录，并且不编辑旧记录。
那些打印语句用于确认 dto.ID 和从前一页收集的 id 匹配，并且确实如此。
在做了一些研究之后，我认为这是因为我需要从数据库中获取当前版本的记录，使用发布的值对其进行更改，然后将其保存回数据库，但我不完全确定如何这样做。
有人可以帮我弄清楚那部分吗？提前谢谢你。
【问题讨论】：
【参考方案1】：不应ToCompletedWC_Inbox 也映射Id。比如：
public WC_Inbox ToCompletedWC_Inbox()
return new WC_Inbox
ID = this.ID, // assuming WC_Inbox has ID property
First_Name = this.First_Name,
....
【讨论】：
是的，这确实是我唯一缺少的东西。我很高兴这是一个简单的修复哈哈谢谢！以上是关于NET Core 6 使用 DTO 更新数据库记录时遇到问题的主要内容，如果未能解决你的问题，请参考以下文章
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