在asp.net web api中动态修改action的名字

在路由设置中，我的路由是这样的：

/api/{controller}/jqGrid/{action}/{id}

对于如下URL，默认情况下执行的是UserController类的List方法：

/api/User/jqGrid/List

而我希望凡是url中含有jqGrid的路由，都执行“jqGrid_{action}”名字的方法，即  jqGrid_List 方法。经过数天地折磨，终于解决了。上代码（这里照搬我在stackoverflow上的提问和我自己的回答了，英语高手欢迎指出文中不地道的英语，谢谢）：

First of all, I need to add a JqGridControllerConfiguration attribute to replace the default action selector applied to the controller with my one.

[JqGridControllerConfiguration]
public class UserController : ApiController
{
    // GET: /api/User/jqGrid/List
    [HttpGet]
    public JqGridModel<User> jqGrid_List()
    {
        JqGridModel<User> result = new JqGridModel<User>();
        result.rows = Get();
        return result;
    }
}

Here's the code of JqGridControllerConfiguration:

public class JqGridControllerConfiguration : Attribute, IControllerConfiguration
{
    public void Initialize(HttpControllerSettings controllerSettings, HttpControllerDescriptor controllerDescriptor)
    {
        controllerSettings.Services.Replace(typeof(IHttpActionSelector), new JqGridActionSelector());
    }
}

in JqGridActionSelector, the "action" is modified if a "jqGrid/" exists in the request URL.

public class JqGridActionSelector : ApiControllerActionSelector
{
    public override HttpActionDescriptor SelectAction(HttpControllerContext controllerContext)
    {
        Uri url = controllerContext.Request.RequestUri;
        if (url.Segments.Any(s => string.Compare(s, "jqGrid/", true) == 0))
        {
            controllerContext.RouteData.Values["action"] = "jqGrid_" + controllerContext.RouteData.Values["action"].ToString();
        }

        return base.SelectAction(controllerContext);
    }
}