具有entity framework和编辑多个对象的MVC 3导致“参照完整性约束违反”

我有一个MVC 3项目，我正在使用Entity Framework作为我的模型。 我有一个对象“雇主”，其中包含“地址”和“邮政地址”，我想同时显示（查看）和更新（编辑）（即在页面上显示雇主详细信息和地址详细信息同时更新） ）

我的观点似乎很好：

var employer = (from e in entities.Employers.Include("Address").Include("PostalAddress") where e.EmployerNumber == employerNumber select e).First(); return View(employer); 

我的编辑显示正常（即所有文本框都填充了雇主和地址详细信息）

 [HttpPost] public ActionResult Edit(Employer employer) { if (ModelState.IsValid) { entities.Employers.Attach(employer); entities.ObjectStateManager.ChangeObjectState(employer, EntityState.Modified); entities.SaveChanges(); return RedirectToAction("Index"); } return View(employer); } 

但是当我去保存时，我在entities.Employers.Attach（雇主）行上得到以下exception：

发生了引用完整性约束违规：定义引用约束的属性值在关系中的主体和从属对象之间不一致。

当我查看它试图附加的雇主对象时，似乎已经“丢失”了它的Address和PostalAddress项目。

这是我的第一个MVC 3项目，所以任何帮助将不胜感激。

编辑页面视图如下所示

 @model MyProject.BusinessObjects.Employer @{ ViewBag.Title = "Edit Employer Details"; } 
Edit Employer Details
 @using (Html.BeginForm()) { @Html.ValidationSummary(true) 
 
Employer
 
Name
 
 @Html.EditorFor(model => model.Name) @Html.ValidationMessageFor(model => model.Name) 
 
 
Address
 
Line One
 
 @Html.EditorFor(model => model.Address.LineOne) @Html.ValidationMessageFor(model => model.Address.LineOne) 
 
Line Two
 
 @Html.EditorFor(model => model.Address.LineTwo) @Html.ValidationMessageFor(model => model.Address.LineTwo) 
 
Suburb
 
 @Html.EditorFor(model => model.Address.Suburb) @Html.ValidationMessageFor(model => model.Address.Suburb) 
 
State
 
 @Html.EditorFor(model => model.Address.State) @Html.ValidationMessageFor(model => model.Address.State) 
 
Post Code
 
 @Html.EditorFor(model => model.Address.PostCode) @Html.ValidationMessageFor(model => model.Address.PostCode) 
 
 
  
 
 } 

 [HttpPost] public ActionResult Edit(Employer employer, FormCollection col) { if (ModelState.IsValid) { var emp = employer; //populate emp.Address and emp.PostalAddress with values from col entities.Employers.Attach(emp); entities.ObjectStateManager.ChangeObjectState(emp, EntityState.Modified); entities.SaveChanges(); return RedirectToAction("Index"); } return View(employer); } 

 public class Employee{ public string Name {get; set;} public Address Address {get; set;} } public class Address { public string Street {get; set;} } 

 public class EmployeeViewModel{ public string Name {get; set;} public string Street {get; set;} }