Passing an JSON array to MVC Web API via GET

No, don't try to be sending JSON in a GET request. Use JSON with other verbs which have body, such as POST and PUT.

Do it the standard way, by decorating your action parameter with the [FromUri] attribute:

public IList<Country> GetCountryList([FromUri] List<long> idList){    ...}

and then just trigger the AJAX request:

$.ajax({    url: 'api/v1/util/CountryList',    type: 'GET',    data: { idList: [1, 2, 3] },    traditional: true,    success: function (result) {        console.log(JSON.stringify(result));    }});

Further recommended reading for you about how the model binding in the Web API works:

http://www.asp.net/web-api/overview/working-with-http/sending-html-form-data,-part-1

**Following are two parameter Enum and objSearch **

var Enum = "ABCD";

var objSearch = [              {"Name":"Navjot Angra","Age":23},              {"Name":"Nav","Age":22}];

//this is ajax method

$.ajax({

   type: "GET",   var GatwayUrl ='http//2937/' (//Your url)   url: GatwayUrl + 'api/Certificate/GetDetail/?Enum=' + Enum +'+&objSearch='+ JSON.stringify(objSearch),   contentType: "application/json; charset=utf-8",   dataType: "json",   success: function (result) {     if (result) {        alert("Your Code");            }       }});

//this part is web api part

[HttpGet]

public IHttpActionResult Fetch([FromUri]string Enum, [FromUri]string objSearch){

IHttpActionResult action=null;return action;

}