hi Shmuel Zang
Thanks for the solution, but i sorted it using another technique that is :
I used post method.
[OperationContract(Name = "TasteList")]
[WebInvoke(Method = "POST", UriTemplate = "/TasteList",
RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
TasteModel TasteList(TasteModel model);