I’ve been learning about OData and wanted to record a quick getting started video with how to create a new WebAPI project, add OData Controller, and send HTTP CRUD operations. Below is an example using Adventure Works Departments with sample code, screenshots, and a 10 minute video introduction. Please leave a comment if you found this helpful. Thanks!

Video Content

Create MVC 4 web application
SQL Express – Adventure Works Departments
Add “AdventureWorks.edmx”
- Wizard driven
- F4 set namespace
Add “DepartmentsController.cs”
- Create from EDMX class
- Implements ODataController
- Replace ID with KEY
Edit “WebApiConfig.cs”
- Comment out default route
- Add OData route builder
Test with HTTP manually
Test with Chrome REST Postman
SQL Express – see changed data

Watch Video

WebAPI OData – 10 min video introduction (Visual Studio 2013) from Jeff Jones on Vimeo.

Sample Code

[WebApiConfig.cs]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http;
using System.Web.Http.OData.Builder;
namespace MvcApplication1
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            //config.Routes.MapHttpRoute(
            //    name: "DefaultApi",
            //    routeTemplate: "api/{controller}/{id}",
            //    defaults: new { id = RouteParameter.Optional }
            //);
            ODataConventionModelBuilder build = new ODataConventionModelBuilder();
            build.EntitySet("Departments");
            config.Routes.MapODataRoute("odata", "odata", build.GetEdmModel());
            config.EnableQuerySupport(new QueryableAttribute()); 
            // Uncomment the following line of code to enable query support for actions with an IQueryable or IQueryable return type.
            // To avoid processing unexpected or malicious queries, use the validation settings on QueryableAttribute to validate incoming queries.
            // For more information, visit http://go.microsoft.com/fwlink/?LinkId=279712.
            //config.EnableQuerySupport();
            // To disable tracing in your application, please comment out or remove the following line of code
            // For more information, refer to: http://www.asp.net/web-api
            config.EnableSystemDiagnosticsTracing();
        }
    }
}

[DepartmentsController.cs]

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web;
using System.Web.Http;
using System.Web.Http.OData;
namespace MvcApplication1.Controllers
{
    public class DepartmentsController : ODataController
    {
        private AdventureWorks2012Entities db = new AdventureWorks2012Entities();
        // GET api/Default1
        public IEnumerable GetDepartments()
        {
            return db.Departments.AsEnumerable();
        }
        // GET api/Default1/5
        public Department GetDepartment(short key)
        {
            Department department = db.Departments.Find(key);
            if (department == null)
            {
                throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotFound));
            }
            return department;
        }
        // PUT api/Default1/5
        public HttpResponseMessage PutDepartment(short key, Department department)
        {
            if (!ModelState.IsValid)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }
            if (key != department.DepartmentID)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest);
            }
            db.Entry(department).State = EntityState.Modified;
            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException ex)
            {
                return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
            }
            return Request.CreateResponse(HttpStatusCode.OK);
        }
        // POST api/Default1
        public HttpResponseMessage PostDepartment(Department department)
        {
            if (ModelState.IsValid)
            {
                db.Departments.Add(department);
                db.SaveChanges();
                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, department);
                response.Headers.Location = new Uri(Url.Link("odata", new { key = department.DepartmentID }));
                return response;
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }
        }
        // DELETE api/Default1/5
        public HttpResponseMessage DeleteDepartment(short key)
        {
            Department department = db.Departments.Find(key);
            if (department == null)
            {
                return Request.CreateResponse(HttpStatusCode.NotFound);
            }
            db.Departments.Remove(department);
            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException ex)
            {
                return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
            }
            return Request.CreateResponse(HttpStatusCode.OK, department);
        }
        protected override void Dispose(bool disposing)
        {
            db.Dispose();
            base.Dispose(disposing);
        }
    }
}