Get FormCollection out controllerContext for Custom Model Binder

Question

I had a nice function that took my FormCollection (provided from the controller). Now I want to do a model bind instead and have my model binder call that function and it needs the FormCollection. For some reason I can find it. I thought it would have been controllerContext.HttpContext.Request.Form

Answer 1

Try this:

var formCollection = new FormCollection(controllerContext.HttpContext.Request.Form)

FormCollection is a type we added to ASP.NET MVC that has its own ModelBinder. You can look at the code for FormCollectionBinderAttribute to see what I mean.

Answer 2

Accessing the form collection directly appears to be frowned on. The following is an example from an MVC4 project where I have a custom Razor EditorTemplate that captures the date and time in separate form fields. The custom binder retrieves the values of the individual fields and combines them into a DateTime.

public class DateTimeModelBinder : DefaultModelBinder
{
    private static readonly string DATE = "Date";
    private static readonly string TIME = "Time";
    private static readonly string DATE_TIME_FORMAT = "dd/MM/yyyy HH:mm";
    public DateTimeModelBinder() { }

    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        if (bindingContext == null) throw new ArgumentNullException("bindingContext");

        var provider = new FormValueProvider(controllerContext);
        var keys = provider.GetKeysFromPrefix(bindingContext.ModelName);
        if (keys.Count == 2 && keys.ContainsKey(DATE) && keys.ContainsKey(TIME))
        {
            var date = provider.GetValue(string.Format("{0}.{1}", bindingContext.ModelName, DATE)).AttemptedValue;
            var time = provider.GetValue(string.Format("{0}.{1}", bindingContext.ModelName, TIME)).AttemptedValue;
            if (!string.IsNullOrWhiteSpace(date) && !string.IsNullOrWhiteSpace(time))
            {
                DateTime dt;
                if (DateTime.TryParseExact(string.Format(System.Globalization.CultureInfo.CurrentCulture, "{0} {1}", date, time),
                                            DATE_TIME_FORMAT,
                                            System.Globalization.CultureInfo.CurrentCulture,
                                            System.Globalization.DateTimeStyles.AssumeLocal,
                                            out dt))
                    return dt;
            }
        }

        return base.BindModel(controllerContext, bindingContext);
    }
}

Answer 3

Use bindingContext.ValueProvider (and bindingContext.ValueProvider.TryGetValue, etc.) to get values directly.