How to create complex .Net objects from json(javascript) in Asp.Net WebApi using RequestCommand

I have succeded in creating simple objects as follows.

The json on the client side js is as follows.

{"Page":1, "Take":10, "SortOrder":"Asc", "PropName":"Id"}

On the webapi side, I have the following class

public class PaginatedRequestCommand
{

    public int Page { get; set; } 

    public int Take { get; set; } 

    public string PropName { get; set; } 

    public string SortOrder { get; set; } 
}

And the WebApiConfig class is as follows

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

    // skiped many other lines as they are not relevant

        config.ParameterBindingRules.Insert(0, typeof(PaginatedRequestCommand),
            x => x.BindWithAttribute(new FromUriAttribute()));

    }
}

And so in Wep Api controller I have the following action method.

    [HttpPost]
    [HttpGet]
    public PaginatedList<PatientCategory> PatCat(PaginatedRequestCommand cmd)
    {
    //......
}

So here I have PaginatedRequestCommand object correctly constructed and the properties Page, Take etc are correctly available. The Angularjs ajax call on the browser is

$http({
            method: 'GET',
            url: this.callParams.uri, // The URI
            params: this.callParams.paginationOptions, // This is where the JSON that showed earlier goes.
            headers: { 'Content-Type': 'application/Json' }
})

Every thing so far so good.

Now I want to pass in some more parameters. I want to include an array in the JSON as follows.

{"Page":1,"Take":10,"SortOrder":"Asc","PropName":"Id",
    "wherePredicateParams":
[{"propName":"Name","val":"s"},
 {"propName":"Description","val":"h"}
]
}

So you see that the "wherePredicateParams" is the additional object that I want to pass. Its an array. What modifications do I have to do on the WebApi side?

I have tried adding the one more property to the PaginatedRequestCommand class, public string[] wherePredicateParams { get; set; } so the full class is as follows.

public class PaginatedRequestCommand
{

    public int Page { get; set; } 

    public int Take { get; set; } 

    public string PropName { get; set; } 

    public string SortOrder { get; set; } 

    public string[] wherePredicateParams { get; set; }
}

This is actually working, in the sense that the property wherePredicateParams of PaginatedRequestCommand object created by the api inside the action method of the above controller is providing me with {"propName":"Name","val":"s"} and {"propName":"Description","val":"h"}. But the problem is I have to parse it my self and use. Is there a better way.

Then I have tried changing string[] to whereParam[] and defined a class

public class whereParam 
{
    public string propName { get; set; }
    public string val { get; set; }
}

So you see the propName and val are null? What am I missing?