Question

Is it possible to pass an ViewModel object to WebApi controller action instead of separate params?

Instead of using:

public class ContactsController : ApiController
{
    public IEnumerable<Contact> GetContacts(string p1, string p2)
    {
        // some logic
    }
}

I would like to use:

public class ContactsController : ApiController
{
    public IEnumerable<Contact> GetContacts(TestVM testVM)
    {
        // some logic
    }
}

public class TestVM
{
    public string P1 { get; set; }
    public string P2 { get; set; }
}

This doesn’t seem to work for me. When I call /api/contacts/?P1=aaa&P2=bbb the testVM object doesn’t get populated (null).

Also, I would like the TestVM to have valdiation attribtues defined and use ModelState.IsValid in my API controller.

Answer 1

Unless told otherwise WebApi will deserialise complex models using the content/body of the request. To tell WebApi to use the Url to construct the model you need to specify the [FromUri] attribute:

public IEnumerable<Contact> GetContacts([FromUri]TestVM testVM)
{
    // some logic
}