Error with Entity Framework add-migration: "value cannot be null"

Question

i am working on an mvc4 asp.net web application. I wanted to add a migration but an error shows on and I don't know how to resolve it. Here's the code of the class:

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>();
}
}
}

and here's the error I get when I want to add a migration:

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

Any help?

your HttpPostedFileBase property might be the problem - what datatype would EF map this to? You can use the [NotMapped] dataannotation to exclude it: http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.schema.notmappedattribute%28v=vs.110%29.aspx — markpsmith
– markpsmith, Commented May 19, 2014 at 10:23
To clarify, this is actually an Entity Framework question. ASP.NET MVC is purely a web technology; ASP.NET projects include Entity Framework by default to handle database access. I've edited the tags accordingly. — anaximander
– anaximander, Commented May 19, 2014 at 11:38

Community · Accepted Answer · 2017-05-23 11:53:39Z

7

Put [NotMapped] attribute on HttpPostedFileBase

See this:

Value cannot be null. Parameter name: extent

edited May 23, 2017 at 11:53

CommunityBot

11 silver badge

answered May 19, 2014 at 10:35

stackunderflow

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Comments

Shaul Behr · Accepted Answer · 2016-07-05 15:13:47Z

5

I am working in EF7. I also got this error, and had no idea what was causing it.

Eventually I tracked it down to the fact that I'd done some namespace refactoring, so my model classes were in different namespaces than they were in the snapshot class (the snapshot class uses strings to qualify the classes!)

I deleted the snapshot file and made a dummy migration to update the snapshot. Then I deleted the dummy migration and thereafter my migrations worked properly again.

answered Jul 5, 2016 at 15:13

Shaul Behr

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3 Comments

Anonymous Duck Over a year ago

thanks solved my error, due to my carelessness the namespace is wrong

Skorek Over a year ago

Thanks dude, you solved my problem I was working on for a few days. I was getting mad about it.

ghosttie Over a year ago

Rebuilding the snapshot fixed my problem - apparently the order of things in the snapshot file matters and it had gotten mixed up when developers merged their changes.

Hussein Zawawi · Accepted Answer · 2014-05-19 11:37:08Z

1

HttpPostedFileBase is a build-in class in System.Web namespace. It wont be recognized by the EF. you can create a wrapper type to persist the data you need it.

answered May 19, 2014 at 11:37

Hussein Zawawi

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