Check Form Attributes
A common mistake people make is missing the following part in the form tag:
<form enctype="multipart/form-data">
</form>
Also in MVC your form structure could look something like this
@using (Html.BeginForm("Action", "Controller", FormMethod.Post, new { @enctype = "multipart/form-data", @id = "myForm", @role="form" }))
