Post model data containg file type using Ajax call in mvc4

Question

I have a ViewModel containing some string and HttpPostedFileBase properties . When i am posting the model to the controller using below ajax call.

 

 

$.ajax({

url: '@Url.Action("_AddFeedback", "Mcq")',

type: 'post',

data: $('form#frm-feedback').serialize(),

success: function (data)

{

alert("done"); },

error: function (data) {

alert("Error occured while saving Option's data."); } });

I am getting value for string but null for HttpPostedFileBase type properties. How can we post HttpPostedFileBase file using ajax ??