asp.net – 如何强制web API来识别querystring参数

但是,如果调用方法,ko参数始终为null.请求下面.
如何修复,以便在查询字符串中传递klient或namepart参数？

Web API v1控制器：

namespace MyApp.Controllers
{
    public class CustomersSearchViewModel
    {
        public string Klient { get; set; }
        public string Namepart { get; set; }
    }


    [Authorize]
    public class CustomersController : ApiController
        {

        public HttpResponseMessage Get(CustomersSearchViewModel ko)
            {
             // why ko is null ?         
             var res = GetCustomers(ko.Klient,ko.Namepart);
             return Request.CreateResponse(HttpStatusCode.OK,new { customers = res.ToArray() } );
            }

        }
    }

控制器被请求调用(appl从erp virtal目录运行)：

GET /erp/api/customers?namepart=kaks&_=1385320904347 HTTP/1.1
Host: localhost:52216
Connection: keep-alive
Accept: application/json,text/javascript,*/*; q=0.01
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML,like Gecko) Chrome/31.0.1650.57 Safari/537.36
Referer: http://localhost:52216/erp/Sale
Accept-Encoding: gzip,deflate,sdch
Accept-Language: et-EE,et;q=0.8,en-US;q=0.6,en;q=0.4
Cookie: .myAuth=8B6B3CFFF3DF64EBEF3D258240D217C56603AF255C869FBB7934560D9F560659342DC4D1EAE6AB28454122A86C3CE6C598FB594E8DC84A; My_Session=5aw2bsjp4i4a5vxtekz

使用默认路由：

config.Routes.MapHttpRoute(
        name: "DefaultApi",routeTemplate: "api/{controller}/{id}",defaults: new { id = RouteParameter.Optional }
    );

应用程序需要运行win Windows 2003服务器,所以Web API v.2不能使用.

更新

我也试过

public HttpResponseMessage Get(string klient,string namepart)

但是在这种情况下返回404错误,没有找到动作.