MVC model binding to nested classes

Question

When I try and create a new 'Flow' class the nested classes ('Action') always come back as null in the controller

So I have classes within classes like so:

public class Flow
{
    private Action actionField
    private string nameField
    private bool enabledField
    ...
}

public class Action
{
    private ActionSchedule actionScheduleField
    private ActionParameter actionParameterField
    private nameField
}
public class ActionSchedule
...

And a single create view for a 'Flow'

@model ProjectZeus.Models.Flow
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
@Html.ValidationSummary(true)

   @Html.TextBoxFor(model => model.name, new { @placeholder = "Flow name" })
   @Html.ValidationMessageFor(model => model.name)


   @Html.LabelFor(model => model.enabled)

   @Html.EditorFor(model => model.enabled)
   @Html.ValidationMessageFor(model => model.enabled)

@Html.Partial("FlowAction")
...

and then partial views for each of the subclasses

@model ProjectZeus.Models.FlowAction

    @Html.TextBoxFor(model => model.name, new { @placeholder = "Action name" })
    ...

I've tried creating instances of the classes and calling the view - error,

I've tried creating instances of the classes in the views themselves - error,

I've tried not using PartialViews:

@Html.TextBoxFor(model => model.action.name, new { @placeholder = "Action name" })

I've googled and googled and googleedddd but with no luck, help please!?

Edit:

Implementing a customer model binder seems like overkill. This page describes the same problem but the solution code won't compile for me ‘The name ‘helper’ does not exist in the current context’? - http://danielhalldev.wordpress.com/2013/08/23/partial-views-and-nested-mvc-model-binding/

Edit2:

I changed the model defintions for brevity - the model is actually auto generated from an xsd:

/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.33440")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
public partial class D53ESBFlow
{

    private D53ESBFlowAction actionField;

    [Required]
    private string nameField;

    ...

    private bool enabledField;

    /// <remarks/>
    public D53ESBFlowAction action
    {
        get
        {
            return this.actionField;
        }
        set
        {
            this.actionField = value;
        }
    }
    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute()]
    public string name
    {
        get
        {
            return this.nameField;
        }
        set
        {
            this.nameField = value;

Edit 3 (bump):

It looks like the 'binder'is creating a property and not a class object?

Answer 1

Did you forget the { get; set; } accessors on the property names?

Answer 2

I had a similar issue with MVC 5, .NET 4.5, Visual Studio 2013.

Here's what worked for me: Add a constructor so the contained class gets instantiated, make them properties (not variables) like AntoineLev said, and add the class to the Binding:

public class Flow
{
    public Action actionField {get; set; }

    public class Flow()
    {
        actionField = new Action();  // otherwise it shows up as null
    }
}

In your controller, Add the the whole class in the binding:

public ActionResult Create([Bind(Include="action,name,enabled")] Flow flow)
{
   ... 
}

Your Mileage may vary.

}