Upload file in MVC4?

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C#

ASP.NET

Javascript

jQuery

MVC4

I have form with different html elements. I want to send the all form data as json and also want o upload file. i successfully collected all form data and convert it into json and passing to the action method. But the problem is i can't able to pass uploaded file also.
please help. My jquery code to send 'json' data to 'SaveForm' action method.

.ajax({
            cache: false,
            type: "POST",
            data:  json,
            async: false,
            url: location.protocol + "//" + location.host + "/Form/SaveForm",
            dataType: "json"
            success: function (Projects) {              
            alert('Form submitted');
            }
        });