3

您好我正在尝试添加一个可以将文件存储到现有 ASP.NET MVC Code First 项目的模型。

namespace MyMVCApp.Models
{
  public class FileUpload
  {
    [Key]
    public int ID { get; set; }
    public string FileName { get; set; }
    public string FilePath { get; set; }

    [Required]
    public HttpPostedFileBase File { get; set; }
  }
}

我在项目DbContext文件中添加了以下内容：

public DbSet<FileUpload> FileUploads { get; set; }

我正在尝试使用包管理器控制台中的实体框架迁移将表添加到现有数据库：

PM> Add-Migration FileUpload

在运行 ubove 命令时，我收到以下错误：

System.Data.Entity.ModelConfiguration.ModelValidationException: One or more validation errors were detected during model generation:

\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'HttpPostedFileBase' has no key defined. Define the key for this EntityType.
\tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'HttpPostedFileBases' is based on type 'HttpPostedFileBase' that has no keys defined.

   at System.Data.Entity.ModelConfiguration.Edm.EdmModelExtensions.ValidateAndSerializeCsdl(EdmModel model, XmlWriter writer)
   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()
One or more validation errors were detected during model generation:

\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'HttpPostedFileBase' has no key defined. Define the key for this EntityType.
\tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'HttpPostedFileBases' is based on type 'HttpPostedFileBase' that has no keys defined.

我错过了什么？

4

1 回答 1

8

您不能使用实体框架保留任意 .NET 类。

为了使实体框架能够持久化它们，必须满足几个要求类，例如在错误中调用的类（未定义键）

确实，您应该尝试仅保留原始类型（int、string 等）和您自己专门设计的类。

在这种情况下，正确的类型是byte[]

这意味着您需要排除在模型上具有属性 HttpPostedFileBase 的可能性。

相反，考虑使用字节数组来存储数据，以及另一个属性，例如字符串来存储文件类型/名称

于 2013-06-24T13:50:59.877 回答