Question

我在MVC4中使用WebAPI。我有一个简单的表单，通过PUT请求将数据提交给API。数据到达并序列化很好，一切看起来都很棒，除了外键没有得到更新。是的，外键存在。

我有以下课程：

public class TriageRecord
{
    [Key]
    public Int64 PKEY { get; set; }
    public DateTime DateAdded { get; set; }
    public DateTime DateUpdated { get; set; }
    public Int64? RecordSource_Id { get; set; }  
    public Int64? AssignedVolunteer_Id { get; set; }  
    public string FacebookID { get; set; }
    public Int64? VANID { get; set; }
    public Int64? NationBuilderID { get; set; }
    public DateTime? DateVanSubmitted { get; set; }
    public Int64? FollowUpLevel_Id { get; set; } 
    public bool? Complete { get; set; }


    public string First { get; set; }
    public string Mid { get; set; }
    public string Last { get; set; }
    public string Email { get; set; }
    public string Address1 { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string Zip5 { get; set; }


    public string HomePhone { get; set; }
    public string CellPhone { get; set; }

    public Int32? EmployeeStatus { get; set; }
    public string StoreNumber { get; set; }
    public virtual WorkArea WorkArea { get; set; }   //put your focus here
    public virtual Department Department { get; set; }
    public virtual Shift Shift { get; set; }


   }

这是我通过表单更新的WorkArea类。

public class WorkArea
{
    [Key]
    public Int64 Id { get; set; }
    [StringLength(200)]
    public string WorkAreaName { get; set; }
}

这是我发布的JSON，它非常适合我的API控制器：

   var saveRecord = function() {
            var record = {
                "PKEY": $("#PKEY").val(),
                "DateAdded": $("#DateAdded").val(),
                "DateUpdated": "@DateTime.Now.ToString()",
                "First": $("#First").val(),
                "Mid": $("#Mid").val(),
                "Last": $("#Last").val(),
                "RecordSource_Id": $("#RecordSource_Id").val(),
                "AssignedVolunteer_Id": $("#AssignedVolunteer_Id").val(),
                "FacebookID": $("#FacebookID").val(),
                "VANID": $("#VANID").val(),
                "NationBuilderID": $("#NationBuilderID").val(),
                "DateVanSubmitted": Date.now(),
                "FollowUpLevel_Id": $("#FollowUpLevel_Id").val(),
                "Complete": $("#Complete").val(),
                "Email": $("#Email").val(),
                "Address1": $("#Address1").val(),
                "City": $("#City").val(),
                "State": $("#State").val(),
                "Zip5": $("#Zip5").val(),
                "HomePhone": $("#HomePhone").val(),
                "CellPhone": $("#CellPhone").val(),
                "EmployeeStatus": $("#EmployeeStatus").val(),
                "StoreNumber": $("#StoreNumber").val(),
                "WorkArea": {
                    "Id": 1,
                    "WorkAreaName": "GM"
                },
                "Department": $("#Department").val(),
                "Shift": $("#Shift").val()                       
            };

它被序列化并且它到达我的控制器，在那里我可以看到当我设置断点时WorkArea（Models.WorkArea）填充了Id = 1＆amp; WorkAreaName =“GM”

所以这是我的控制器：

  public HttpResponseMessage PutTriageRecord(long id, TriageRecord triagerecord)
    {
        if (id == triagerecord.PKEY)  //breakpoint here shows triagerecord contains workarea values
        {                
            db.Entry(triagerecord).State = EntityState.Modified;                
            try
            {                    
            db.SaveChanges();  //changes get saved for everything (ie, first name) but not workarea...
            }
            catch (DbUpdateConcurrencyException)
            {
                return Request.CreateResponse(HttpStatusCode.NotFound);
            }

            return Request.CreateResponse(HttpStatusCode.OK);
        }
        else
        {
            return Request.CreateResponse(HttpStatusCode.BadRequest);
        }
    }

除了WorkArea之外，我的TriageRecord中的所有内容都已更新...为什么？

更新：不工作。这就是我添加到控制器中的内容......它只是在WorkAreas表中创建了大量的内容。

  public HttpResponseMessage PutTriageRecord(long id, TriageRecord triagerecord)
    {
        if (id == triagerecord.PKEY)  //breakpoint here shows triagerecord contains workarea values
        {                
            db.Entry(triagerecord).State = EntityState.Modified;                
            try
            {      
                db.TriageRecords.Attach(triagerecord);   //attach
                db.Entry(triagerecord.WorkArea).State = EntityState.Added;   //add           
            db.SaveChanges();  //WORKS!
            }
            catch (DbUpdateConcurrencyException)
            {
                return Request.CreateResponse(HttpStatusCode.NotFound);
            }

            return Request.CreateResponse(HttpStatusCode.OK);
        }
        else
        {
            return Request.CreateResponse(HttpStatusCode.BadRequest);
        }
    }

Answer 1

您需要调用Attach并将子对象的状态设置为Added。它与WebApi没有任何关系，这就是EF在处理分离对象时的工作方式（例如，当您将它们发送到客户端和返回时）。数据库上下文跟踪的是更改，因此当您使用分离的对象时，它不会自动修改添加的内容。

“如果你不打电话给孩子保持分离，直到SaveChanges 被称为EF将假设它们是新实体（因为它们没有附加到上下文）并将其状态设置为已添加。然后他们将被插入数据库。“

EF 4.3 CF does not update relationships when saving changes

“EF外键（或实体？）没有级联/更新

1 个答案: