创建基于OData的Web API - Knowledge Builder API， Part III：Write Model

using System;

namespace knowledgebuilderapi.Models {
    public enum KnowledgeCategory: Int16 {
        Concept     = 0,
        Formula     = 1,
    }
}

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace knowledgebuilderapi.Models {
    public abstract class BaseModel {

        [Column("CreatedAt")]
        public DateTime CreatedAt { get; set; }
        [Column("ModifiedAt")]
        public DateTime ModifiedAt { get; set; }
    }
}

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace knowledgebuilderapi.Models
{
    [Table("Knowledge")]
    public class Knowledge : BaseModel
    {

        [Key]
        public Int32 ID { get; set; }
        [Required]
        [Column("ContentType")]
        public KnowledgeCategory Category { get;set; }
        [Required]
        [MaxLength(50)]
        [ConcurrencyCheck]
        [Column("Title", TypeName = "NVARCHAR(50)")]
        public string Title { get;set; }
        [Required]
        [Column("Content")]
        public string Content { get;set; }
        [Column("Tags")]
        public string Tags { get; set; }
    }
}

using System;
using Microsoft.EntityFrameworkCore;

namespace knowledgebuilderapi.Models
{
    public class kbdataContext : DbContext
    {
        public kbdataContext(DbContextOptions options) : base(options)
        { }

        public DbSet Knowledges { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity()
                .Property(b => b.CreatedAt)
                .HasDefaultValueSql("getdate()");
            modelBuilder.Entity()
                .Property(b => b.ModifiedAt)
                .HasDefaultValueSql("getdate()");
            modelBuilder.Entity()
                .Property(e => e.Category)
                .HasConversion(
                    v => (Int16)v,
                    v => (KnowledgeCategory)v);
        }
    }
}

using System;
using Microsoft.AspNet.OData;
using Microsoft.EntityFrameworkCore;
using knowledgebuilderapi.Models;
using System.Linq;

namespace knowledgebuilderapi.Controllers {
    public class KnowledgeController : ODataController {
        private readonly kbdataContext _context;

        public KnowledgeController(kbdataContext context)
        {
            _context = context;
        }

        [EnableQuery]
        public IQueryable Get()
        {
            return _context.Knowledges;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNet.OData.Extensions;
using Microsoft.AspNet.OData.Builder;
using Microsoft.AspNet.OData.Batch;
using knowledgebuilderapi.Models;
using Microsoft.AspNetCore.Routing;

namespace knowledgebuilderapi
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }
        public string ConnectionString { get; private set; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            this.ConnectionString = Configuration["KBAPI.ConnectionString"];

            services.AddDbContext(options =>
                options.UseSqlServer(this.ConnectionString));

            services.AddMvc(action => {
                action.EnableEndpointRouting = false;
            }).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
            services.AddOData();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();

            ODataModelBuilder modelBuilder = new ODataConventionModelBuilder(app.ApplicationServices);
            modelBuilder.EntitySet("Knowledges");
            modelBuilder.Namespace = typeof(Knowledge).Namespace;

            var model = modelBuilder.GetEdmModel();
            app.UseODataBatching();

            app.UseMvc(routeBuilder =>
                {
                    // and this line to enable OData query option, for example $filter
                    routeBuilder.Select().Expand().Filter().OrderBy().MaxTop(100).Count();

                    routeBuilder.MapODataServiceRoute("ODataRoute", "odata", model);
                });
        }
    }
}

cd knowledgebuilderapi
dotnet run

edmx:Edmx xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx" Version="4.0">
edmx:DataServices>
Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="knowledgebuilderapi.Models">
EntityType Name="Knowledge">
Key>
PropertyRef Name="ID"/>
Key>
Property Name="ID" Type="Edm.Int32" Nullable="false"/>
Property Name="Category" Type="knowledgebuilderapi.Models.KnowledgeCategory" Nullable="false"/>
Property Name="Title" Type="Edm.String" Nullable="false" MaxLength="50"/>
Property Name="Content" Type="Edm.String" Nullable="false"/>
Property Name="Tags" Type="Edm.String"/>
Property Name="CreatedAt" Type="Edm.DateTimeOffset" Nullable="false"/>
Property Name="ModifiedAt" Type="Edm.DateTimeOffset" Nullable="false"/>
EntityType>
EnumType Name="KnowledgeCategory" UnderlyingType="Edm.Int16">
Member Name="Concept" Value="0"/>
Member Name="Formula" Value="1"/>
EnumType>
EntityContainer Name="Container">
EntitySet Name="Knowledges" EntityType="knowledgebuilderapi.Models.Knowledge">
Annotation Term="Org.OData.Core.V1.OptimisticConcurrency">
Collection>
PropertyPath>TitlePropertyPath>
Collection>
Annotation>
EntitySet>
EntityContainer>
Schema>
edmx:DataServices>
edmx:Edmx>