How to bind posted data named "file[]" to an MVC model?

Question

I am using Redactor as an HTML editor, which has a component for uploading images and files.

Redactor takes care of the client side bit, and I need to provide the server side upload functionality.

I have no problem getting the uploads to work if I use Request.Files in the controller.

But I would like to bind the posted files to a Model, and I seem unable to do this, because the parameter they are sent with is files[] - with square brackets in the name.

My question:

Is it possible to bind the posted "file[]" to an MVC model? It's an invalid property name, and using file alone doesn't work.

---

This file input looks like this. I can specify a name other than file, but Redactor adds [] to the end, regardless of the name.

<input type="file" name="file" multiple="multiple" style="display: none;">

I am trying to bind to a property like this:

public HttpPostedFileBase[] File { get; set; }

When I watch the upload take place, I see this in the request (I presume that redactor may be adding the square brackets behind the scenes):

Content-Disposition: form-data; name="file[]"; filename="my-image.jpg"

Also relevant:

Redactor always sends the uploading request with content-type as multipart/form-data. So you don't need to add this enctype anywhere

Answer 1

You should create a custom model binder to bind uploaded files to one property. First create a model with a HttpPostedFileBase[] property

public class RactorModel
{
    public HttpPostedFileBase[] Files { get; set; }
}

then implement DefaultModelBinder and override BindProperty

public class RactorModelBinder : DefaultModelBinder
{
    protected override void BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor)
    {
        int len = controllerContext.HttpContext.Request.Files.AllKeys.Length;

        if (len > 0)
        {
            if (propertyDescriptor.PropertyType == typeof(HttpPostedFileBase[]))
            {
                string formName = string.Format("{0}[]", propertyDescriptor.Name);
                HttpPostedFileBase[] files = new HttpPostedFileBase[len];
                for (int i = 0; i < len; i++)
                {
                    files[i] = controllerContext.HttpContext.Request.Files[i];
                }

                propertyDescriptor.SetValue(bindingContext.Model, files);
                return;
            }
        }

        base.BindProperty(controllerContext, bindingContext, propertyDescriptor);
    }
}

Also you should add binder provider to your project, then register it in global.asax

public class RactorModenBinderProvider : IModelBinderProvider
{
    public IModelBinder GetBinder(Type modelType)
    {
        if (modelType == typeof(RactorModel))
        {
            return new RactorModelBinder();
        }

        return null;
    }
}
...
ModelBinderProviders.BinderProviders.Insert(0, new RactorModenBinderProvider());

this isn't a general solution, but I guess you get the point.