Update Navigation Properties with Entity Framework (MVC3 Razor) - asp.net-mvc

Question

I'm having trouble figuring out how to get my navigation property to update with the Entity Framework. I used a database first approach and set up all appropriate FK relationships. Here's what the two tables I'm working with look like:
Rate Profile
RateProfileID
ProfileName
Rate
RateID
RateProfileID (FK)
Several Other Properties I Want to Update
One RateProfile can/will have many Rates. I built my edit page for RateProfile to display editors for the RateProfile Entity and all of it's associated Rate entities and stuck all of that in a form with a submit button. I can display everything just fine, but my changes will only persist for the model class (RateProfile) and not for its navigation property (Rates).
Below are my views/HttpPost Edit/ Models
In my HttpPost Edit method, you can see my feeble attempt to loop through and Update each record in the navigation property Rates of the model.
#model PDR.Models.RateProfile
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<legend>RateProfile</legend>
#Html.HiddenFor(model => model.RateProfileID)
#Html.HiddenFor(model => model.LoginID)
<div class="editor-label">
#Html.LabelFor(model => model.ProfileName)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.ProfileName)
#Html.ValidationMessageFor(model => model.ProfileName)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.isDefault)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.isDefault)
#Html.ValidationMessageFor(model => model.isDefault)
</div>
<div>
<fieldset>
<legend>Dime</legend>
<table>
<tr>
<th>
Min
</th>
<th>
Max
</th>
<th>
Price
</th>
<th></th>
</tr>
#foreach (var rate in Model.Rates)
{
<tr>
<td>
#Html.EditorFor(modelItem => rate.minCount)
#Html.ValidationMessageFor(model => rate.minCount)
</td>
<td>
#Html.EditorFor(modelItem => rate.maxCount)
#Html.ValidationMessageFor(model => rate.maxCount)
</td>
<td>
#Html.EditorFor(modelItem => rate.Amount)
#Html.ValidationMessageFor(model => rate.Amount)
</td>
</tr>
}
</table>
</fieldset>
<p>
<input type="submit" value="Save" />
</p>
</fieldset>
}
[HttpPost]
public ActionResult Edit(RateProfile rateprofile)
{
if (ModelState.IsValid)
{
db.Entry(rateprofile).State = EntityState.Modified;
foreach (Rate rate in rateprofile.Rates)
{
db.Entry(rate).State = EntityState.Modified;
}
db.SaveChanges();
return RedirectToAction("Index");
}
return View(rateprofile);
}
public partial class Rate
{
public int RateID { get; set; }
public int RateProfileID { get; set; }
public string Size { get; set; }
public decimal Amount { get; set; }
public int minCount { get; set; }
public int maxCount { get; set; }
public int PanelID { get; set; }
public virtual Panel Panel { get; set; }
public virtual RateProfile RateProfile { get; set; }
}
public partial class RateProfile
{
public RateProfile()
{
this.Rates = new HashSet<Rate>();
}
public int RateProfileID { get; set; }
public string ProfileName { get; set; }
public int LoginID { get; set; }
public bool isDefault { get; set; }
public virtual Login Login { get; set; }
public virtual ICollection<Rate> Rates { get; set; }
}

Answer 1

You change the foreach into for statement and try whether the model binding is working fine or not.
#for (var int i = 0; i < Model.Rates; i++)
{
<tr>
<td>
#Html.EditorFor(modelItem => Model.Rates[i].minCount)
#Html.ValidationMessageFor(model => Model.Rates[i].minCount)
</td>
<td>
#Html.EditorFor(modelItem => Model.Rates[i].maxCount)
#Html.ValidationMessageFor(model => Model.Rates[i].maxCount)
</td>
<td>
#Html.EditorFor(modelItem => Model.Rates[i].Amount)
#Html.ValidationMessageFor(model => Model.Rates[i].Amount)
</td>
</tr>
}

Answer 2

So what happens when you put a breakpoint on your Edit foreach statement and check what's in rateprofile.Rates ?
Remember that a model returning from a view is not the original object you handed out, it's a disconnected one that was created from scratch in your controller function.
Also, why is Rates a Hashset? Don't mix your database referential constraints with your UI ones, as it only adds to the confusion :)
What Mark suggested here is correct. The fields on the form should be named things like Rates[0].ProfileName, Rates[1].ProfileName etc, but as you have a HashSet, I'm not sure how MVC would regenerate those into the model.
Test with the breakpoint, then follow Mark's suggestion, and I would suggest you replace HashSet with an array or list.