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c#entity-frameworkasp.net-web-apiodataodata-v4
Hanu
Hanu

Reputation: 173

Web APi OData V4 Issue "The entity '' does not have a key defined

When I run the following sample it is throwing the following exception...

Additional information: The entity 'TestEntity' does not have a key defined.

I have configured the key using code first entity context... modelBuilder.Entity<TestEntity>().HasKey(t => t.EntityID);

What is the issue? why is OData V4 not using the configured key?

namespace WebApplication2
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services

            // Web API routes
            config.MapHttpAttributeRoutes();

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );

            config.MapODataServiceRoute("odata", "odata", model: GetEDMModel());

        }

        private static IEdmModel GetEDMModel()
        {
            ODataModelBuilder builder = new ODataConventionModelBuilder();
            builder.EntitySet<TestEntity>("TestEntities");             
            return builder.GetEdmModel();
        }
    }


    public class TestEntity
    {
        public int EntityID { get; set; }
        public string Name { get; set; }
    }

    public partial class TestContext1 : DbContext
    {

        public TestContext1() : base("DB")
        {
        }
        public DbSet<TestEntity> Entities { get; set; }        
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<TestEntity>().HasKey(t => t.EntityID);

        }
    }

}

Upvotes: 15

Views: 17959

Answers (3)

Ben Anderson
Ben Anderson

Reputation: 7353

I came here from google and ran into this error, here is an example of what my class looked like

public class TestEntity
{
    [Key]
    public int EntityID { get; }//<-- missing set
    public string Name { get; set; }
}

only after I added the set to my [key] property did it get resolved. Here is the end result

public class TestEntity
{
    [Key]
    public int EntityID { get; set; }//<--- added set
    public string Name { get; set; }
}

Upvotes: 10

GH.Ezzat
GH.Ezzat

Reputation: 31

if the class name is TestEntity and the id field is EntityID this is the problem change the class name to Entity or the field name to Id or TestEntityId this worked for me ,you can check this link for more solutions if this wasn't the case.

Upvotes: 0

woelliJ
woelliJ

Reputation: 1504

You defined the key for the database mapping of Entity Framework but not for the OData mapping.

Try this:

 private static IEdmModel GetEDMModel()
 {
       ODataModelBuilder builder = new ODataConventionModelBuilder();
       var entitySet = builder.EntitySet<TestEntity>("TestEntities");
       entitySet.EntityType.HasKey(entity => entity.EntityID)
       return builder.GetEdmModel();
 }

Or try adding a [Key] Attribute to your TestEntity to tell OData (and Entity Framework at the same time) what Property is the key.

Like so:

using System.ComponentModel.DataAnnotations;

public class TestEntity
{
    [Key]
    public int EntityID { get; set; }
    public string Name { get; set; }
}

Upvotes: 35

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