实体框架代码优先方法和ModelValidationException [英] Entity Framework Code-First Aproach and ModelValidationException

问题描述

我正在构建MVC应用程序，并在构建实体和数据库时尝试使用代码优先的方式.

I'm building an MVC application and trying to use code-first aproach while building entities and database.

运行代码时得到ModelValidationException. (消息: System.Data.Entity.ModelConfiguration.ModelValidationException'发生在EntityFramework.dll中，但未在用户代码中处理)

I get ModelValidationException when I run code. (Message: System.Data.Entity.ModelConfiguration.ModelValidationException' occurred in EntityFramework.dll but was not handled in user code)

这是代码:

控制器:

public class HomeController : Controller {
    PhonesDB _db = new PhonesDB();

    public ActionResult Index() {
        var model = from b in _db.ProductList //Exception appears here
                    select b;
        return View(model);
    }
}

模型:

namespace SmartPhoneCatalog.Models {
    public class Products {
        public int ProductID { get; set; }
        public string Manufacturer { get; set; }
        public string Name { get; set; }
        //...
    }
}

namespace SmartPhoneCatalog.Models {
    public class PhonesDB:DbContext {
        public DbSet<Products> ProductList { get; set; }
    }
}

这是视图:

@model IEnumerable<SmartPhoneCatalog.Models.Products>

@{
    ViewBag.Title = "Home";
}

@foreach (var item in Model) {
    <div>
        <h4>@item.Name</h4>
        <div>@item.Price</div>
        <hr/>
    </div>
}

我想念什么吗?

试图先启动空的mvc应用程序，然后再启动模板，但两者都存在相同的问题.

Tried starting empty mvc application and then template but had the same problem on both one.

用var model = _db.ProductList.ToList();替换LINQ并没有帮助.还尝试编辑PhonesDB模型(更改为粗体):

Replacing LINQ with var model = _db.ProductList.ToList(); didn't help. Also tried editing PhonesDB model(changes are in bold):

public **partial** class PhonesDB : DbContext {
    public PhonesDB():**base("PhonesDB")**{
    }

    **protected override void OnModelCreating(DbModelBuilder modelBuilder) {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    }**

    public DbSet<Products> ProductList { get; set; }
}

仍然出现相同的异常. 有任何解决方法的想法吗?

still getting same exception. Any ideas how to fix it?

推荐答案

该异常似乎隐藏了真正的异常.我的猜测是，由于您的ProductId字段上没有[Key]属性，因此引发了真正的异常:

That exception looks to be hiding the real exception. My guess is that the real exception is being thrown because you don't have a [Key] attribute on your ProductId field:

public class Products {
    [Key]
    public int ProductID { get; set; }
    public string Manufacturer { get; set; }
    public string Name { get; set; }
    //...
}

此处是有关Code First使用的属性的更多信息

Here is some more info about the attributes used by Code First

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