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我正在使用mvc4 asp.net web应用程序。我想添加一个迁移，但显示一个错误，我不知道如何解决它。 这里的类代码：实体框架添加迁移错误：“值不能为空”
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;
namespace POCOs
{
public class Consultant
{
public int Id { get; set; }
public string Nom { get; set; }
public string Prenom { get; set; }
public string RefCommercial { get; set; }
public string DateNaissance { get; set; }
public int CIN { get; set; }
public string Fonction { get; set; }
public string Tel { get; set; }
public string Experience { get; set; }
public string Email { get; set; }
public HttpPostedFileBase CV { get; set; }
public ICollection<Prestation> prestations { get; set; }
public Consultant()
{
prestations = new HashSet<Prestation>();
}
}
}
和这里的时候，我想补充一个迁移是我得到的错误：
Add-Migration
cmdlet Add-Migration at command pipeline position 1
Supply values for the following parameters:
Name: cv
System.ArgumentNullException: Value cannot be null.
Parameter name: key
at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
at System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value)
at System.Data.Entity.ModelConfiguration.Configuration.Mapping.SortedEntityTypeIndex.Add(EdmEntitySet entitySet, EdmEntityType entityType)
at System.Data.Entity.ModelConfiguration.Configuration.Mapping.EntityMappingService.Analyze()
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.ConfigureEntityTypes(DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.Configure(DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest, DbProviderInfo providerInfo)
at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.LazyInternalContext.get_CodeFirstModel()
at System.Data.Entity.Infrastructure.EdmxWriter.WriteEdmx(DbContext context, XmlWriter writer)
at System.Data.Entity.Migrations.Extensions.DbContextExtensions.<>c__DisplayClass1.<GetModel>b__0(XmlWriter w)
at System.Data.Entity.Migrations.Extensions.DbContextExtensions.GetModel(Action`1 writeXml)
at System.Data.Entity.Migrations.Extensions.DbContextExtensions.GetModel(DbContext context)
at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext)
at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.GetMigrator()
at System.Data.Entity.Migrations.Design.ToolingFacade.GetPendingMigrationsRunner.RunCore()
at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.Run()
Value cannot be null.
Parameter name: key
任何帮助吗？
您的HttpPostedFileBase属性可能是问题 - EF将映射到哪个数据类型？您可以使用[NotMapped]数据注解来排除它：[http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.schema.notmappedattribute%28v=vs.110%29.aspx]（ http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.schema.notmappedattribute%28v=vs.110%29.aspx） – markpsmith
为了澄清，这实际上是一个实体框架问题。 ASP.NET MVC纯粹是一种Web技术; ASP.NET项目默认包含Entity Framework来处理数据库访问。我已经相应地编辑了标签。 – anaximander