Model state validation is easy with DataAnnotations. However, you will find repeating the next line of code very soon:
…
if(!ModelState.IsValid) return BadRequest(..);
…
Luckily, there is a pretty simple solution – to use ActionFilter:
| using System; | |
| using System.Net; | |
| using System.Net.Http; | |
| using System.Web.Http.Controllers; | |
| using System.Web.Http.Filters; | |
| namespace MyAwesomeWebApi.ActionFilters | |
| { | |
| /// <summary> | |
| /// Returns 400 if the ModelState is invalid. | |
| /// </summary> | |
| [AttributeUsage(AttributeTargets.All, AllowMultiple = false, Inherited = true)] | |
| public class ValidateModelAttribute : ActionFilterAttribute | |
| { | |
| public override void OnActionExecuting(HttpActionContext actionContext) | |
| { | |
| if (actionContext.ModelState.IsValid) | |
| return; | |
| actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState); | |
| } | |
| } | |
| } |
| using System.Collections.Generic; | |
| using System.Threading.Tasks; | |
| using System.Web.Http; | |
| using System.Web.Http.Description; | |
| using System.ComponentModel.DataAnnotations; | |
| namespace MyAwesomeWebApi.Controllers | |
| { | |
| public class ValuesController : ApiController | |
| { | |
| [ValidateModel] | |
| public IHttpActionResult Post(MyModel model) | |
| { | |
| var valService = new ValService(); | |
| var result = valService.Create(model); | |
| return Created($"api/values/{result.Id}", result); | |
| } | |
| } | |
| public class MyModel | |
| { | |
| [Required] | |
| public int Id { get; set; } | |
| } | |
| } |
All you have to do is to add the ValidateModel attribute to your controller methods that require model state validation.
