{
  "Columns": 
    [
    {"ID": "Int"},
    {"Name": "String"},
    ],
  "Rows": 
    [
    ["1","John Smith"],
    ["2","Mary Williams"]    
    ]
}

[ 
   {
     "ID":1,
    "Name":"John Smith"
   },
   {
     "ID":"2",
     "Name":"Marry Williams"
   }
]

using System;
using System.IO;
using System.Web;
using System.Web.Mvc;

public class ModelBinder<TResult> : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        HttpRequestBase request = controllerContext.HttpContext.Request;
        string requestData;
        Stream requestStream = request.InputStream;

        requestStream.Seek(0, SeekOrigin.Begin);

        using (var reader = new StreamReader(requestStream))
        {
            requestData = reader.ReadToEnd();
        }

        try
        {
            return Deserialize(requestData);
        }
        catch (Exception ex)
        {
            ex.Data.Add("Request.Data", requestData);
            throw ex;
        }
    }

    protected TResult Deserialize<TResult>(string requestData)
    {
        // Тут пишешь код нужной тебе десериализации
    }
}