c# - Web APi OData V4 问题 "The entity ' ' 没有定义键

Question

当我运行以下示例时，它抛出以下异常...

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

我已经使用代码优先实体上下文配置了 key ... modelBuilder.Entity<TestEntity>().HasKey(t => t.EntityID);

问题是什么？为什么 OData V4 没有使用配置的 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);

        }
    }

}

Answer 1

您为 Entity Framework 的数据库映射定义了键，但没有为 OData 映射定义键。

试试这个:

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

或者尝试向您的 TestEntity 添加一个 [Key] 属性来告诉 OData(同时还有 Entity Framework)什么属性是键。

像这样:

using System.ComponentModel.DataAnnotations;

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