经过几天的努力,我终于得到了这份工作。
我有一个简单的人员和部门数据库:
我可以使用强类型的ASP.NET MVC视图作为参考/导航属性!查看部门列表......
ASP.NET MVC with DropDownList http://img11.imageshack.us/img11/7619/dropdownlistdepartment.gif
我的人物/编辑视图的一部分:
<% 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>
<% } %>
我的Person控制器的一部分:
//
// 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");
}
为了实现这一点,我使用新的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);
}
}
}
}
我使用新的AttachUpdated和ApplyReferencePropertyChanges方法扩展了Entity Framework ObjectContext:
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;
}
}
}
}
我只想在此记录我的进展。请提出改进建议。
感谢:
答案 0 :(得分:8)
我已经开始使用ASP.NET MVC,这就是我遇到这个帖子的原因,所以我不确定你是否还在检查改进。
我不喜欢将新属性添加到实体框架的部分类中,因为它不允许进行太多更改。 尝试像这样标记你的Deparment DropDown“Department.Id”
<p>
<label for="Department.Id">Department:</label>
<%= Html.DropDownList("Department.Id", new SelectList((IEnumerable)ViewData["Departments"], "Id", "Name"))%>
</p>
MVC框架的ModelBinding将获取值并将其应用于“Department”导航属性的“Id”属性。我发现Department的其他值是null,但这并不重要。现在,您可以检索正确的部门实体,并将其应用于在模型绑定到Action参数中创建的新Person实体的部门导航属性,如:
newPerson.Department = ctx.Department.First(d => d.DepartmentId == newPerson.Department.Id);
以这种方式执行此操作时,您根本不需要为其应具有的属性更新您的实体。
答案 1 :(得分:0)
改进Edit控件,以便它处理抛出的异常并重新显示用户到目前为止输入的输入。我相信你一定要去;)
更新您的观点以获得验证码:
<label for="Name">Name:</label>
<%= Html.TextBox("Name", Model.Name) %>
<%= Html.ValidationMessage("Name", "*") %>
然后在编辑中使用它们:
[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);
}
}