ASP.NET MVC 5 HttpPostedFileBase always null - asp.net-mvc

Question

I checked everything and can't figure it out. The Form is multipart/form-data, the name of the input matches the name of the variable in the post method, and still the file is always null and Request.Files is always empty.
#model Gnosis.View.Areas.OpportunityAction.Models.Rfp.RfpModel
#using (Html.BeginForm(MVC.OpportunityAction.ChangeRfp.Edit(), FormMethod.Post, new { enctype = "multipart/form-data", id="submitForm" }))
{
<input type="file" name="file" id="file" style="width: 400px"/>
}
controller method
[HttpPost]
public virtual ActionResult Edit(HttpPostedFileBase file, RfpModel model)
{
}
If I do an ajax post that works, but I should work with MVC mechanisms also and can't figure it out why it doesn't...
Update. This is the code in the view:
#model Gnosis.View.Areas.OpportunityAction.Models.Rfp.RfpModel
#using (Html.BeginForm(MVC.OpportunityAction.ChangeRfp.Edit(), FormMethod.Post, new { enctype = "multipart/form-data", id="submitForm" }))
{
#Html.HiddenFor(m => m.Id)
#Html.HiddenFor(m => m.SystemEditDate)
#Html.AntiForgeryToken()
#Html.HiddenFor(m => m.Attachment)
#Html.HiddenFor(m => m.Description)
#Html.HiddenFor(m => m.FileSize)
#Html.HiddenFor(m => m.FileDate)
#Html.HiddenFor(m => m.FileTime)
#Html.HiddenFor(m => m.FileExtension)
#Html.HiddenFor(m => m.OpportunityRfpId)
<table class="keyvalue withrowpadding">
<tr>
<td class="key">#Html.LabelFor(m => m.Rfp)</td>
<td class="value">#Html.EditorFor(m => m.Rfp)</td>
</tr>
<tr>
<td class="key">#Html.LabelFor(m => m.RfpDate)</td>
<td class="value">#Html.EditorFor(m => m.RfpDate)</td>
</tr>
<tr>
<td class="key">#Html.LabelFor(m => m.FileName)</td>
<td class="value">#Html.TextBox("NameForDisplay", Model.FileName, new {disabled = "disabled", style = "width:300px"})</td>
</tr>
<tr>
<td class="key">RFP File Name:</td>
<td class="value"><input type="file" name="file" id="file" style="width: 400px"/> #Html.ValidationMessageFor(m => m.Attachment)</td>
</tr>
<tr>
<td></td>
<td>
<input type="submit" name="submit" value="Save" id="Save"/>
<input type="button" value="Cancel"/>
</td>
</tr>
</table>
#Html.ValidationSummary()
}
<script>
$(document).on('click', '#Save', function () {
var vcfData = new FormData($('#submitForm')[0]);
var rfp = $("#Rfp").val();
var rfpDate = $("#RfpDate").val();
var id = $("#Id").val();
var opportunityRfpId = $("#OpportunityRfpId").val();
console.log(id);
$.ajax({
url: '#Url.Action(MVC.OpportunityAction.ChangeRfp.SubmitFile())' + "?file=" + vcfData + '&id=' + id + '&Rfp=' + rfp + '&RfpDate=' + rfpDate + '&OpportunityRfpId='+ opportunityRfpId,
type: "post",
data: vcfData,
processData: false,
contentType: false,
cache: false,
success: function (data) {
}
});
});
</script>
The code is inherited, and probably the original developer couldn't figure out this puzzle either so he did the ajax post. But I need to expand this functionality, and it needs to be done in the Edit method and dependent on processing of this file...