Reading JSON data returned from ASP.NET MVC

you can read like this

 var a = [{ "ServiceId": 4, "ServiceName": "first sevice", "ServiceCriteria": "Lumpsum", "ItemBasis": "Inward/Outward", "Currency": null, "Amount": null}];
        alert(a[0].ServiceId);

Your controller side must be like this

public string SelectService(string ServiceId, string ServiceName, string ServiceCriteria, string ItemBasis, string Currency, string Amount)
{
    string message = string.Empty;
    //do whatever you want here and return message like 
    message=success;
    return message;
}

Than in view page check if return value is success or not.

    success: function (data) {               
         if(data=="success" )
         {
            //to do
            $("#Services").empty();
         }
         else
         { 
            //bla bla
         }
   },
   error: function (reponse) {
   alert("error : " + reponse);
   }

I'm assuming that your JSON string is returned by the controller. You can access the return data in the success callback. Your data variable already contains this response.

$('#btnservice').click(function () {
    var url = "/Quotation/SelectService/";
    var selservice = $("#selservice").val();

    $.ajax({
        url: url,
        data: { selservice: selservice },
        cache: false,               
        dataType: 'json',
        type: "POST",
        success: function (data) {               
            var service = data[0];

            alert(service.ServiceName); // Should be "first service"

            $("#Services").empty();
        },
        error: function (reponse) {
            alert("error : " + reponse);
        }
    });
});

I use following code and it works good:

success: function (data) {
     $.each(data, function (index, item) {
     alert(data[index].ServiceId)
     alert(data[index].ServiceName)    
     .............................
     .............................
     //other properties you want to get                      
     });
    }