MVC C# Automatic Model Binding in Nested Lists

Question

This is my first ever C# / MVC project and I am having problems binding to a model. I have read an applied Phil Haack's Post and have used EditorFor for all my partial views. Do I need a custom Model Binder? Please help

In brief, I have a list of weeks which contain a list of entries. These entries contain a list of hours

Action:

[HttpPost]
public ActionResult SubmitRecords(List<WeekCollection> itemData)
{
     //do stuff
     return View();
}

Model:

public class WeekCollection
{
    public WeekCollection()
    {
        this.OneWeek = new List<Entry>();
    }

    public List<Entry> OneWeek { get; set; }
}

[Bind(Exclude = "Task, Project")]
public class Entry
{
    public int ProjectId { get; set; }
    public virtual Projects Project { get; set; }

    public int TaskId { get; set; }
    public virtual Tasks Task { get; set; }

    public bool Billable { get; set; }
    public List<Hours> Gethours { get; set; }
}

public class Hours
{
    public float NumberOfHours { get; set; }
}

Views (Index)

//within partial view iteration with incrementing u (u++)
@using(@Html.BeginForm())
{ 
    @Html.EditorFor(m => m[u].OneWeek, "TimesheetWeek")
    <input type="Submit">
}

Views (TimesheetWeek)

@foreach (var value in Model)
{
    v++;
    if (Model.All(x => x.projectId == 0))
    {
        @Html.DropDownListFor(p => p[v].projectId, (IEnumerable<SelectListItem>)projectList, "Select Project", new { @class = "notSelect" })
        @Html.DropDownListFor(t => t[v].taskId, (IEnumerable<SelectListItem>)taskList, "Select Task", new { @class = "notSelect" })
     }
     else
     {
        if (value.projectId != 0)
        {    
           @Html.DropDownListFor(p => p[v].projectId, (IEnumerable<SelectListItem>)projectList, new Dictionary<string, Object> { { "class", "SelectDrop" }, { "data-selectHead", value.projectId } })
           @Html.DropDownListFor(t => t[v].taskId, (IEnumerable<SelectListItem>)taskList, new Dictionary<string, Object> { { "class", "SelectDrop" }, { "data-selectHead", value.taskId } })
        }
     }

     @Html.CheckBoxFor(b => b[v].billable)
     @Html.EditorFor(h => h[v].gethours, "HoursDisplay")

     @value.gethours.Sum(a => a.numberOfHours)
     }

View (HoursDisplay)

@for (var i = 0; i < Model.Count(); i++)
{
    @Html.TextBoxFor(m => m[i].numberOfHours)
}

Model displays all the data correctly and the form data output posted is as follows:

[0].OneWeek.[0].projectId:1
[0].OneWeek.[0].taskId:1
[0].OneWeek.[0].billable:true
[0].OneWeek.[0].billable:false
[0].OneWeek.[0].gethours.[0].numberOfHours:0
[0].OneWeek.[0].gethours.[1].numberOfHours:5
[0].OneWeek.[0].gethours.[2].numberOfHours:7
[0].OneWeek.[0].gethours.[3].numberOfHours:6
[0].OneWeek.[0].gethours.[4].numberOfHours:4
[0].OneWeek.[0].gethours.[5].numberOfHours:8
[0].OneWeek.[0].gethours.[6].numberOfHours:0

I thought I got the indexing right but currently get an empty Oneweek in the action. What am I doing wrong? Any assistance is appreciated. (Some repetition and HTML has been removed)

Answer 1

Your prefixes are wrong. For example:

[0].OneWeek.[0].projectId:1

should be:

[0].OneWeek[0].projectId:1

You have an extra dot ( . ). Read Phil Haack's article once again for the correct syntax when binding with lists.

You have the same problem with the gethours.[0] part.

I would recommend you using the standard editor templates conventions and avoid writing any foreach loops and dealing with indexes:

~/Views/Home/Index.cshtml:

@model List<WeekCollection>
@using(Html.BeginForm())
{ 
    @Html.EditorForModel()
    <input type="Submit" />
}

~/Views/Home/EditorTemplates/WeekCollection.cshtml :

@model WeekCollection
@Html.EditorFor(x => x.OneWeek)

~/Views/Home/EditorTemplates/Entry.cshtml :

@model Entry
...