在MVC 3.0中将JSON返回给Action

 viewModel.updateCoder = function (coder) {
   var coderJson = ko.toJSON(coder);
   var coderJsonString = ko.utils.stringifyJson(coderJson);
   $.ajax({
     url: \"provider/UpdateCoder\",
     type: \'POST\',
     dataType: \'text\',
     data: coderJsonString,
     contentType: \'text/csv\',
     success: function () { alert(\"Updated!\"); }
   });

 routes.MapRoute(
    \"UpdateCoder\",
      \"provider/UpdateCoder/{coderDTO}\", // URL with parameters
    new { controller = \"Provider\", action = \"UpdateCoder\", coderDTO = UrlParameter.Optional }
    );

[AcceptVerbs(HttpVerbs.Post)]
public string UpdateCoder( string coderDTO )
{
  var rslt = \"success\";
  //var coder = coderDTO.CoderDTOToCoder();
  return rslt;
}

[AcceptVerbs(HttpVerbs.Post)]
public string UpdateCoder( **CoderDTO coderDTO** )
{
  var rslt = \"success\";
  //var coder = coderDTO.CoderDTOToCoder();
  return rslt;
}

public class CoderDTO
{
    public Int32 Id { get; set; }
    public String CoderCode { get; set; }
    public String Sal { get; set; }
    public String LName { get; set; }
    public String FName { get; set; }
    public String MI { get; set; }
    public String Facility { get; set; }
    public String Title { get; set; }
    public Boolean? IsContract { get; set; }
    public Boolean? IsInactive { get; set; }
    public Boolean? IsDeleted { get; set; }
    public String Comments { get; set; }
    public String AlternateId { get; set; }
    public int CasesCoded { get; set; }

    public CoderDTO(Coder coder)
    {
        Id = coder.Id;
        CoderCode = coder.CoderCode;
        Sal = coder.Sal;
        LName = coder.LName;
        FName = coder.FName;
        MI = coder.MI;
        Facility = coder.Facility;
        Title = coder.Title;
        if (coder.IsContract != null) IsContract = coder.IsContract;
        if (coder.IsInactive != null) IsInactive = coder.IsInactive;
        if (coder.IsDeleted != null) IsDeleted = coder.IsDeleted;
        Comments = coder.Comments;
        AlternateId = coder.AlternateId;
    }

    public Coder CoderDTOToCoder()
    {
        var coder = new Coder
                    {
                        Id = Id,
                        CoderCode = CoderCode,
                        Sal = Sal,
                        LName = LName,
                        FName = FName,
                        MI = MI,
                        Facility = Facility,
                        Title = Title
                    };
        coder.IsContract = IsContract ?? false;
        coder.IsInactive = IsInactive ?? false;
        coder.IsDeleted = IsDeleted ?? false;
        coder.Comments = Comments;
        coder.AlternateId = AlternateId;
        return coder;
    }


}

{\"Id\":201,\"CoderCode\":\"GP \",\"Sal\":null,\"LName\":null,\"FName\":null,\"MI\":null,\"IsContract\":false,\"IsInactive\":false,\"Comments\":null,\"CasesCoded\":0,\"isBeingEdited\":false}