mvc genericly binding byte[] properties - asp.net-mvc-5

Question

I've tried using a custom model binder but my request.files is not populated. IN forms collection, the input of type file for the byte[] property is populated by file name only.
<input id="collection[#index].#p.Name" name="collection[#index].#p.Name" type="file" />
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace male.services.mvc.Binders
{
public class CustomModelBinder : DefaultModelBinder
{
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
if (bindingContext.ModelType.GetProperties().Any(o => o.PropertyType == typeof(byte[])))
{
HttpRequestBase request = controllerContext.HttpContext.Request;
foreach (var pi in bindingContext.ModelType.GetProperties().Where(o => o.PropertyType == typeof(byte[])))
{
// can't access any property in the parameters that gives me my file input or my stream
}
return base.BindModel(controllerContext, bindingContext);
}
else
{
return base.BindModel(controllerContext, bindingContext);
}
}
}
}

Answer 1

I found the answer. This will allow me to go straight from html file inputs to EF models without resorting to hand-crafting a file argument for each model type and property type which needs it. (Aint nobody got time for that)
In order for a form to post files, it must have the enctype attribute:
<form enctype="multipart/form-data" ... />
Once that is done, the file can be accessed via controllerContext.HttpContext.Request.Files
UPDATE - Working Example
Note: You don't need the Regex stuff if you aren't trying to bind a collection. You also don't need the EndsWith, you can just use ==
using System.ComponentModel;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Web;
using System.Web.Mvc;
namespace male.services.mvc.Binders
{
public class CustomModelBinder : DefaultModelBinder
{
HttpRequestBase request;
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
request = controllerContext.HttpContext.Request;
return base.BindModel(controllerContext, bindingContext);
}
protected override void BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor)
{
if (propertyDescriptor.PropertyType == typeof(byte[]))
{
var key = request.Files.AllKeys.SingleOrDefault(o => o.EndsWith($"].{propertyDescriptor.Name}"));
var fileIndex = Regex.Match(key, #"\[(.*)\]").Groups[1].Value;
var modelIndex = Regex.Match(bindingContext.ModelName, #"\[(.*)\]").Groups[1].Value;
if(fileIndex == modelIndex)
{
HttpPostedFileWrapper httpPostedFile = (HttpPostedFileWrapper)request.Files[request.Files.AllKeys.SingleOrDefault(o => o.EndsWith(propertyDescriptor.Name))];
using (MemoryStream ms = new MemoryStream())
{
httpPostedFile.InputStream.CopyTo(ms);
propertyDescriptor.SetValue(bindingContext.Model, ms.ToArray());
}
}
}
else
base.BindProperty(controllerContext, bindingContext, propertyDescriptor);
}
}
}