c# - MVC EntityFramework 代码优先迁移 - Seed() 因 AmbiguousMatchException 而失败？

Question

我正在开发一个有点简单的 InventoryTracker MVC5 应用程序，其中我在将 LocalDatabase 设置为 Seed() 时遇到了一些问题.

当我运行 update-database在我的下面的代码上执行命令，我在 context.INV_Assets.AddRange(invAssets) 行得到如下异常:

An exception of type 'System.Reflection.AmbiguousMatchException' occurred in mscorlib.dll but was not handled in user code. Additional information: Ambiguous match found.

任何人对我的 INV_Assets - Seed() 中的内容有任何想法导致问题？没有 InnerException，我似乎无法获得更多详细信息。

---

代码:

internal sealed class Configuration : DbMigrationsConfiguration<InventoryTracker.DAL.InventoryTrackerContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
    }

    protected override void Seed(InventoryTracker.DAL.InventoryTrackerContext context)
    {
        if (System.Diagnostics.Debugger.IsAttached == false)
        {
            System.Diagnostics.Debugger.Launch();
        }

        List<INV_Locations> invLocs = getLocations();
        context.INV_Locations.AddRange(invLocs);
        context.SaveChanges(); 
        List<INV_Manufacturers> invManufacturers = getManufacturers();
        context.INV_Manufacturers.AddRange(invManufacturers);
        context.SaveChanges();
        List<INV_Models> invModels = getModels();
        context.INV_Models.AddRange(invModels);
        context.SaveChanges();
        List<INV_Statuses> invStatuses = getStatuses();
        context.INV_Statuses.AddRange(invStatuses);
        context.SaveChanges();
        List<INV_Types> invTypes = getTypes();
        context.INV_Types.AddRange(invTypes);
        context.SaveChanges();
        List<INV_Vendors> invVendors = getVendors();
        context.INV_Vendors.AddRange(invVendors);
        context.SaveChanges(); // Everything OK to this point.

        List<INV_Assets> invAssets = getAssets();
        context.INV_Assets.AddRange(invAssets); // System.Reflection.AmbiguousMatchException!

        context.SaveChanges();
    }

    private List<INV_Assets> getAssets()
        {
            List<INV_Assets> testAssets = new List<INV_Assets>
            {
              new INV_Assets
              {
                Id = 1,
                ip_address = "10.10.135.38",
                mac_address = "10.10.177.44",
                note = "",
                owner = "John Smith",
                cost = 35,
                po_number = "G348",
                invoice_number = 1447,
                serial_number = "JX14582Y",
                asset_tag_number = "293548195023",
                //acquired_date = Convert.ToDateTime(10212014),
                acquired_date = DateTime.ParseExact("10212014", "MMddyyyy", CultureInfo.InvariantCulture),
                disposed_date = null,
                created_by = "Admin",
                created_date = DateTime.Now,
                modified_by = "Admin",
                modified_date = DateTime.Now,
                Location_Id = 1,
                Manufacturer_Id = 1,
                Model_Id = 1,
                Status_Id = 2,
                Type_Id = 3,
                Vendor_Id = 3
            }
        };
        return testAssets;
    }

---

编辑:

INV_Assets.cs:

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using GridMvc.DataAnnotations;
using System.Web.Mvc;
using InventoryTracker.Models;

namespace InventoryTracker.Models
{
    [GridTable(PagingEnabled = true, PageSize = 30)]
    public class INV_Assets
    {
        // Setting GridColumn Annotations allows you to use AutoGenerateColumns on view to auto create the Grid based on the model.


        public int Id { get; set; }

        public int Model_Id { get; set; }
        [ForeignKey("Model_Id")]
        public virtual INV_Models model_id { get; set; }

        [Required]
        public int Manufacturer_Id { get; set; }
        [ForeignKey("Manufacturer_Id")]
        public virtual INV_Manufacturers manufacturer_id { get; set; }

        [Required]
        public int Type_Id { get; set; }
        [ForeignKey("Type_Id")]
        public virtual INV_Types type_id { get; set; }

        [Required]
        public int Location_Id { get; set; }
        [ForeignKey("Location_Id")]
        public virtual INV_Locations location_id { get; set; }

        public int Vendor_Id { get; set; }
        [ForeignKey("Vendor_Id")]
        public virtual INV_Vendors vendor_id { get; set; }

        [Required]
        public int Status_Id { get; set; }
        [ForeignKey("Status_Id")]
        public virtual INV_Statuses status_id { get; set; }

        public string ip_address { get; set; }

        public string mac_address { get; set; }

        public string note { get; set; }
        public string owner { get; set; }
        public decimal cost { get; set; }
        public string po_number { get; set; }


        public int invoice_number{ get; set; }

        [Required]
        public string serial_number { get; set; }

        [Required]
        public string asset_tag_number { get; set; }

        [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
        public DateTime? acquired_date { get; set; }

        [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
        public DateTime? disposed_date { get; set; }

        [Required]
        [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
        public DateTime created_date { get; set; }

        [Required]
        public string created_by { get; set; }

        [DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}")]
        public DateTime modified_date { get; set; }

        public string modified_by { get; set; }

        // Flag to specify if item is available? (Not signed out, not auctioned, recycled, etc.)
        //public bool available { get; set; }
    }
}

---

EDIT2:

完整结果 Package Manager Console从输入命令 update-database结果 Ambiguous Match found :

PM> update-database
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
No pending explicit migrations.
Running Seed method.
System.Reflection.AmbiguousMatchException: Ambiguous match found.
   at System.RuntimeType.GetPropertyImpl(String name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers)
   at System.Type.GetProperty(String name, BindingFlags bindingAttr)
   at System.Linq.Expressions.Expression.PropertyOrField(Expression expression, String propertyOrFieldName)
   at System.Data.Entity.Core.Objects.Internal.EntityProxyFactory.CreateBaseGetter(Type declaringType, PropertyInfo propertyInfo)
   at System.Data.Entity.Core.Objects.Internal.PocoPropertyAccessorStrategy.GetNavigationPropertyValue(RelatedEnd relatedEnd)
   at System.Data.Entity.Core.Objects.Internal.EntityWrapper`1.GetNavigationPropertyValue(RelatedEnd relatedEnd)
   at System.Data.Entity.Core.Objects.EntityEntry.FixupFKValuesFromNonAddedReferences()
   at System.Data.Entity.Core.Objects.ObjectContext.AddSingleObject(EntitySet entitySet, IEntityWrapper wrappedEntity, String argumentName)
   at System.Data.Entity.Core.Objects.ObjectContext.AddObject(String entitySetName, Object entity)
   at System.Data.Entity.Internal.Linq.InternalSet`1.<AddRange>b__f(Object entity)
   at System.Data.Entity.Internal.Linq.InternalSet`1.ActOnSet(Action`1 action, EntityState newState, IEnumerable entities, String methodName)
   at System.Data.Entity.Internal.Linq.InternalSet`1.AddRange(IEnumerable entities)
   at System.Data.Entity.DbSet`1.AddRange(IEnumerable`1 entities)
   at InventoryTracker.Migrations.Configuration.Seed(InventoryTrackerContext context) in c:\James-Projects\InventoryTracker\InventoryTracker\Migrations\Configuration.cs:line 91
   at System.Data.Entity.Migrations.DbMigrationsConfiguration`1.OnSeed(DbContext context)
   at System.Data.Entity.Migrations.DbMigrator.SeedDatabase()
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.SeedDatabase()
   at System.Data.Entity.Migrations.DbMigrator.Upgrade(IEnumerable`1 pendingMigrations, String targetMigrationId, String lastMigrationId)
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.Upgrade(IEnumerable`1 pendingMigrations, String targetMigrationId, String lastMigrationId)
   at System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration)
   at System.Data.Entity.Migrations.DbMigrator.<>c__DisplayClassc.<Update>b__b()
   at System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
   at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.Run()
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Update(String targetMigration, Boolean force)
   at System.Data.Entity.Migrations.UpdateDatabaseCommand.<>c__DisplayClass2.<.ctor>b__0()
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
Ambiguous match found.

Answer 1

您的问题出在非常相似的属性名称中。例如在 INV_Assets 你有

public int Model_Id { get; set; }

[ForeignKey("Model_Id")]
public virtual INV_Models model_id { get; set; }

两者的名字几乎相同。区别仅在于第一个符号大小写。基于堆栈跟踪和 Entity Framework 源，它在 EntityProxyFactory 类中做这样的事情:

public virtual Func<object, object> CreateBaseGetter(Type declaringType, PropertyInfo propertyInfo)
{
  Func<object, object> nonProxyGetter = 
        ((Expression<Func<object, object>>) (instance 
            => 
                Expression.PropertyOrField(
                    (Expression) Expression.Convert(instance, declaringType),
                    propertyInfo.Name))
        ).Compile();

它将属性名称作为字符串传递。并且 Reflection 无法理解它应该使用什么属性，因为有两个属性具有相同的名称和不同的大小写。

这是一个具有相同逻辑的示例程序，它也因相同的找到不明确的匹配项而失败。异常 - https://dotnetfiddle.net/BUIAwK

像往常一样，在属性名称中使用 ID 命名的引用对象，因此您只需将代码更新为

public int Model_Id { get; set; }

[ForeignKey("Model_Id")]
public virtual INV_Models Model { get; set; }