DataMember's Name property is ignored with [FromUri] property in WebApi service

Question

We are creating RestService with Asp.Net WebApi. But for some reason Name property is ignored in DataMember attribute when trying to deserialize complex property with [FromURI] attribute.

For example we might have: Method:

public IHttpActionResult Get([FromUri]User user)

Model:

[DataContract]
public class User
{
    [DataMember(Name = "username")]
    public string Username{ get; set; }
    [DataMember(Name = "isActive", IsRequired = false)]
    public bool? Active { get; set; }
}

When deserializing user we get username as expected, but null for Active. On the other hand when serializing data we get both isActive and username as expected. If we send request with active in query string it works as expected.

It's obviously problem with IModelBinder. It doesn't use DataMember's Name property for some reason. I checked what formaters are included and 4 default ones are registered:

System.Net.Http.Formatting.JsonMediaTypeFormatter
System.Net.Http.Formatting.XmlMediaTypeFormatter
System.Net.Http.Formatting.FormUrlEncodedMediaTypeFormatter
System.Net.Http.Formatting.JQueryMvcFormUrlEncodedFormatter

I don't have a way to check which one is used on request. I would assume that its FormUrlEncodedMediaTypeFormatter but I can't be sure. Also, I am not sure if it even supports Name property.

I already checked for a solution and closest topic I could find was WebAPI DataMember Name not used when de/serializing via application/x-www-form-urlencoded but it doesn't use [FromUri] but application/x-www-form-urlencoded property and it wasn't really solved.

Any ideas, pointers or suggestions would be much appreciated.

Answer 1

Use [FromQuery] instead other attributes.

And model for your request http://localhost:8080/api/users?username=John&isActive=true

[Route("api/users")]
public class UsersController : Controller
{
    [HttpGet]
    public IHttpActionResult Get(User user)
    {
        //...
    }
}

Will looks like

public class User
{
    [FromQuery(Name = "username")]
    public string Username{ get; set; }
    [FromQuery(Name = "isActive")]
    public bool? Active { get; set; }
}

Anyway best practice is to keep names in model as it parameters names in query. In this case you dont have to provide "Name" parameter, only keep [FromQuery] on queryClass, and lower casing .Net provide automaticly.

Answer 2

You must check your "get" request. Your get request must be like this;

GET api/foo?username=fooname&active=false

You don't have to DataContract and DataMember attribute to just achieve this. These attribute just for another thing, its not the main reason to use for.

After get valid hit on your get method, in your method you can check modelstate like;

if (ModelState.IsValid) {
/// your code goes here    
}