MVC 2实体框架视图模型插入 [英] MVC 2 Entity Framework View Model Insert
问题描述
这是推动我疯了。希望我的问题是有道理的......
This is driving me crazy. Hopefully my question makes sense...
我使用MVC 2和Entity Framework 1，我试图插入新记录有两个导航属性。
I'm using MVC 2 and Entity Framework 1 and am trying to insert a new record with two navigation properties.
我有一个SQL表，关键字，具有查找表CategoryTypes和另一个自参照查找CategoryParent。 EF使我的分类模型中的两个导航属性，一个叫父母和另一个叫CategoryType，各自车型的两个实例。
I have a SQL table, Categories, that has a lookup table CategoryTypes and another self-referencing lookup CategoryParent. EF makes two nav properties on my Category model, one called Parent and another called CategoryType, both instances of their respective models.
在我的观点，即创建新的类别，我有两个下拉菜单，一个用于CategoryType，另一个用于ParentCategory。当我尝试插入新的类别没有ParentCategory，这使得空，一切都很好。当我加入ParentCategory，插入失败，奇怪的（或因此我认为）抱怨此错误的形式CategoryType：
On my view that creates the new Category, I have two dropdowns, one for the CategoryType and another for the ParentCategory. When I try and insert the new Category WITHOUT the ParentCategory, which allows nulls, everything is fine. As soon as I add the ParentCategory, the insert fails, and oddly (or so I think) complains about the CategoryType in the form of this error:
相关'CategoryTypes被发现了。 1'CategoryTypes'的预期。
0 related 'CategoryTypes' were found. 1 'CategoryTypes' is expected.
当我步，我可以verifiy这两个ID属性来在行动方法的参数是正确的。我还可以验证，当我去到数据库来获取CategoryType和ParentCategory用的ID，该记录被拉到罚款。然而，失败的SaveChanges上（）。
When I step through, I can verifiy that both ID properties coming in on the action method parameter are correct. I can also verify that when I go to the db to get the CategoryType and ParentCategory with the ID's, the records are being pulled fine. Yet it fails on SaveChanges().
所有我能看到的是，在我看来，我的CategoryParent dropdownlistfor，以某种方式导致插入轰炸。
All that I can see is that my CategoryParent dropdownlistfor in my view, is somehow causing the insert to bomb.
请看看我的意见，我httpPost创建操作方法。
Please see my comments in my httpPost Create action method.
我的视图模型是这样的：
My view model looks like this:
public class EditModel
{
public Category MainCategory { get; set; }
public IEnumerable<CategoryType> CategoryTypesList { get; set; }
public IEnumerable<Category> ParentCategoriesList { get; set; }
}
我创建的操作方法是这样的：
My Create action methods look like this:
// GET: /Categories/Create
public ActionResult Create()
{
return View(new EditModel()
{
CategoryTypesList = _db.CategoryTypeSet.ToList(),
ParentCategoriesList = _db.CategorySet.ToList()
});
}
// POST: /Categories/Create
[HttpPost]
public ActionResult Create(Category mainCategory)
{
if (!ModelState.IsValid)
return View(new EditModel()
{
MainCategory = mainCategory,
CategoryTypesList = _db.CategoryTypeSet.ToList(),
ParentCategoriesList = _db.CategorySet.ToList()
});
mainCategory.CategoryType = _db.CategoryTypeSet.First(ct => ct.Id == mainCategory.CategoryType.Id);
// This db call DOES get the correct Category, but fails on _db.SaveChanges().
// Oddly the error is related to CategoryTypes and not Category.
// Entities in 'DbEntities.CategorySet' participate in the 'FK_Categories_CategoryTypes' relationship.
// 0 related 'CategoryTypes' were found. 1 'CategoryTypes' is expected.
//mainCategory.Parent = _db.CategorySet.First(c => c.Id == mainCategory.Parent.Id);
// If I just use the literal ID of the same Category,
// AND comment out the CategoryParent dropdownlistfor in the view, all is fine.
mainCategory.Parent = _db.CategorySet.First(c => c.Id == 2);
_db.AddToCategorySet(mainCategory);
_db.SaveChanges();
return RedirectToAction("Index");
}
下面是我在视图中创建表单：
Here is my Create form on the view :
<% using (Html.BeginForm()) {%>
<%= Html.ValidationSummary(true) %>
<fieldset>
<legend>Fields</legend>
<div>
<%= Html.LabelFor(model => model.MainCategory.Parent.Id) %>
<%= Html.DropDownListFor(model => model.MainCategory.Parent.Id, new SelectList(Model.ParentCategoriesList, "Id", "Name")) %>
<%= Html.ValidationMessageFor(model => model.MainCategory.Parent.Id) %>
</div>
<div>
<%= Html.LabelFor(model => model.MainCategory.CategoryType.Id) %>
<%= Html.DropDownListFor(model => model.MainCategory.CategoryType.Id, new SelectList(Model.CategoryTypesList, "Id", "Name"))%>
<%= Html.ValidationMessageFor(model => model.MainCategory.CategoryType.Id)%>
</div>
<div>
<%= Html.LabelFor(model => model.MainCategory.Name) %>
<%= Html.TextBoxFor(model => model.MainCategory.Name)%>
<%= Html.ValidationMessageFor(model => model.MainCategory.Name)%>
</div>
<div>
<%= Html.LabelFor(model => model.MainCategory.Description)%>
<%= Html.TextAreaFor(model => model.MainCategory.Description)%>
<%= Html.ValidationMessageFor(model => model.MainCategory.Description)%>
</div>
<div>
<%= Html.LabelFor(model => model.MainCategory.SeoName)%>
<%= Html.TextBoxFor(model => model.MainCategory.SeoName, new { @class = "large" })%>
<%= Html.ValidationMessageFor(model => model.MainCategory.SeoName)%>
</div>
<div>
<%= Html.LabelFor(model => model.MainCategory.HasHomepage)%>
<%= Html.CheckBoxFor(model => model.MainCategory.HasHomepage)%>
<%= Html.ValidationMessageFor(model => model.MainCategory.HasHomepage)%>
</div>
<p><input type="submit" value="Create" /></p>
</fieldset>
<% } %>
也许我刚刚熬夜太晚摆弄MVC 2？ :)请让我知道如果我不是足够清晰。
Maybe I've just been staying up too late playing with MVC 2? :) Please let me know if I'm not being clear enough.
有些事情我已经因为提出这个问题改变。我想我关门？
我的新创建的操作方法：
My new Create action method:
private DbEntities _db = new DbEntities();
// POST: /Categories/Create
[HttpPost]
public ActionResult Create(Category mainCategory)
{
if (!ModelState.IsValid)
return View(new EditModel()
{
MainCategory = mainCategory,
CategoryTypesList = _db.CategoryTypeSet.ToList(),
ParentCategoriesList = _db.CategorySet.ToList()
});
int parentId = 2; // Accessories in db.
short typeId = 1; // Product type in db.
mainCategory.ParentReference.EntityKey = new EntityKey("DbEntities.CategorySet", "Id", parentId);
mainCategory.CategoryTypeReference.EntityKey = new EntityKey("DbEntities.CategoryTypeSet", "Id", typeId);
_db.AddToCategorySet(mainCategory);
_db.SaveChanges();
return RedirectToAction("Index");
}
我也注释掉我的两个dropdownlists等mainCategory这些属性不被实例化。
I've also commented out my two dropdownlists so those properties on "mainCategory" don't get instantiated.
所以，用2导航属性现在空的，我用两个文字为ID的，它完美的作品。最后，我想用从mainCategory父母CategoryType的标识的，但这似乎不工作。可能是一个很好的理由，我不知道的？
So, with the 2 nav properties null now, I use two literals for the Id's and it works perfectly. Ultimately, I want to use the Id's of Parent and CategoryType from mainCategory, but this seems to not work. Probably a good reason I'm not aware of?
推荐答案
你有没有尝试设置的EntityReference像
Did you try setting the EntityReference like
mainCategory.CategoryTypeReference.EntityKey = new EnityKey("YourEntities", "Id", mainCategory.CategoryType.Id);
这样你不会有加载您CategoryType它可能会解决你的问题。
that way you wont have to load your CategoryType and it might resolve your problem.
修改：我张贴的样本是不完整的，对不起，这里是你应该做的。
EDIT: The sample i posted is not complete, sorry, here is what you should do
int parentId = mainCategory.Parent.Id;
short typeId = mainCategory.CategoryType.Id;
mainCategory.Parent = null;
mainCategory.CategoryType = null;
mainCategory.ParentReference.EntityKey = new EntityKey("DbEntities.CategorySet", "Id", parentId);
mainCategory.CategoryTypeReference.EntityKey = new EntityKey("DbEntities.CategoryTypeSet", "Id", typeId);
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