使用ADO.NET实体框架的强类型ASP.NET MVC

Question

经过几天的努力，我终于得到了这个工作。

我得人和部门的一个简单的数据库：

ADO.NET Entity Framework Entity Data Model diagram with Department and Person objects http://img39.imageshack.us/img39/1368/edmxdepartmentperson.gif

我可以借鉴/导航性能强类型ASP.NET MVC的意见！见部门列表...我的人/编辑观点的

ASP.NET MVC with DropDownList http://img11.imageshack.us/img11/7619/dropdownlistdepartment.gif

部分：

<% using (Html.BeginForm()) {%> 
    <%= Html.Hidden("Id", Model.Id) %> 
    <fieldset> 
     <legend>Fields</legend> 
     <p> 
      <label for="Name">Name:</label> 
      <%= Html.TextBox("Name", Model.Name) %> 
     </p> 
     <p> 
      <label for="DepartmentId">Department:</label> 
      <%= Html.DropDownList("DepartmentId", new SelectList((IEnumerable)ViewData["Departments"], "Id", "Name"))%> 
     </p> 
     <p> 
      <input type="submit" value="Save" /> 
     </p> 
    </fieldset> 
<% } %> 

我一个人控制器的部分：

// 
// GET: /Person/Edit/5 

public ActionResult Edit(Guid id) 
{ 
    ViewData["Departments"] = ctx.Department; 
    Person model = (from Person p in ctx.Person 
        where p.Id == id 
        select p).FirstOrDefault(); 
    return View(model); 
} 

// 
// POST: /Person/Edit 

[AcceptVerbs(HttpVerbs.Post)] 
public ActionResult Edit(Person model) 
{ 
    ctx.AttachUpdated(model); //extension 
    ctx.SaveChanges(); 
    return RedirectToAction("Index"); 
} 

为了得到这个工作，我用新的DepartmentId属性扩展了Person EntityObject。

using System; 
using System.Data; 
using System.Data.Objects.DataClasses; 

namespace ProjectName.Models 
{ 
    public partial class Person : EntityObject 
    { 
     public Guid DepartmentId 
     { 
      get 
      { 
       try 
       { 
        return (Guid)this.DepartmentReference.EntityKey.EntityKeyValues[0].Value; 
       } 
       catch 
       { 
        return Guid.Empty; 
       } 
      } 
      set 
      { 
       this.DepartmentReference.EntityKey = new EntityKey("JunkEntities.Department", "Id", value); 
      } 
     } 
    } 
} 

我延长了实体框架ObjectContext的新AttachUpdated和ApplyReferencePropertyChanges方法：

using System; 
using System.Data; 
using System.Data.Objects; 
using System.Data.Objects.DataClasses; 

public static class EntityFrameworkExtensionMethods 
{ 

    public static void AttachUpdated(this ObjectContext ctx, EntityObject objectDetached) 
    { 
     if (objectDetached.EntityKey == null) 
     { 
      String entitySetName = ctx.DefaultContainerName + "." + objectDetached.GetType().Name; 
      Guid objectId = (Guid)objectDetached.GetType().GetProperty("Id").GetValue(objectDetached, null); 
      objectDetached.EntityKey = new System.Data.EntityKey(entitySetName, "Id", objectId); 
     } 
     if (objectDetached.EntityState == EntityState.Detached) 
     { 
      object currentEntityInDb = null; 
      if (ctx.TryGetObjectByKey(objectDetached.EntityKey, out currentEntityInDb)) 
      { 
       ctx.ApplyPropertyChanges(objectDetached.EntityKey.EntitySetName, objectDetached); 
       ctx.ApplyReferencePropertyChanges((IEntityWithRelationships)objectDetached, 
                (IEntityWithRelationships)currentEntityInDb); //extension 
      } 
      else 
      { 
       throw new ObjectNotFoundException(); 
      } 
     } 
    } 

    public static void ApplyReferencePropertyChanges(this ObjectContext ctx, IEntityWithRelationships newEntity, IEntityWithRelationships oldEntity) 
    { 
     foreach (var relatedEnd in oldEntity.RelationshipManager.GetAllRelatedEnds()) 
     { 
      var oldRef = relatedEnd as EntityReference; 
      if (oldRef != null) 
      { 
       var newRef = newEntity.RelationshipManager.GetRelatedEnd(oldRef.RelationshipName, oldRef.TargetRoleName) as EntityReference; 
       oldRef.EntityKey = newRef.EntityKey; 
      } 
     } 
    } 

} 

我只是想在这里记录我的进步。请提出改进​​建议。

---

感谢：

• Alex James
• Cesar de la Torre
• Griff Townsend
• Steve Willcock
• jrista
• Tomas Lycken
• Thomas Levesque
• Danny Simmons
• Stefan Cruysberghs

Answer 1

我已经开始与ASP工作.NET MVC这就是为什么我来到这个线程，所以我不知道你是否还在检查改进。

我不喜欢将新属性添加到实体框架上的部分类的想法，因为它不允许有太多改变。 尝试标记您的Deparment DropDown“部门。ID”这样

<p> 
    <label for="Department.Id">Department:</label> 
<%= Html.DropDownList("Department.Id", new SelectList((IEnumerable)ViewData["Departments"], "Id", "Name"))%> 
</p> 

的MVC框架的ModelBinding将拿起值，并将其应用到‘部门‘导航属性Id’的属性’。我发现的是，部门的其他值现在你有一种方法来检索正确的部门实体并将其应用到在模型绑定到你的动作参数中创建的新人物实体的部门导航属性中，如下所示：

newPerson.Department = ctx.Department.First(d => d.DepartmentId == newPerson.Department.Id); 

newPerson.Department = ctx.Department.First(d => d.DepartmentId == newPerson.Department.Id); 

通过这种方式，您不需要更新您的实体就可以拥有它应该拥有的房产。

Answer 2

提高你的编辑控制，使其处理被抛出的异常并重新显示输入用户在目前输入。我敢肯定你正要;）

更新你的看法有验证：

<label for="Name">Name:</label> 
<%= Html.TextBox("Name", Model.Name) %> 
<%= Html.ValidationMessage("Name", "*") %> 

，然后利用它们在你的编辑：

[AcceptVerbs(HttpVerbs.Post)] 
public ActionResult Edit(Person Model) 
{ 
    try 
    { 
     ctx.AttachUpdated(Model); //extension 
     ctx.SaveChanges(); 
     return RedirectToAction("Index"); 
    } 
    catch 
    { 
     foreach (var err in Model.Errors) 
      ModelState.AddModelError(err.PropertyName, err.ErrorMessage) 

     return View(Model); 
    } 
}