Question

I am a bit lost here as I have not really looked at model binders so if possible, can one advise me if I am actually thinking about my problem correctly… 🙂 and if my code is way of, please advise…

1 -I have a DTO class which contains ‘custom fields’ each with a name and other properties i.e.:

Public Class CustomFields
{
 public string Name {get;set;}
 public string Description {get;set;}
 public string FieldType {get;set;}
 public string Value {get;set;}
}

2- Within my repo/business layer I am setting the values and returning ICollection for the view to render

3- the view uses a foreach to display fields

<% foreach (var item in Model) {%>
   <div class="editor-label">
      <%= Html.Label(item.Name) %>
   </div>
   <div class="editor-field">
      <%= Html.TextBox(item.Name, item.Value)%>
   </div>
<% } %>

Question: What is the best way to retrieve the result via a post? If there are errors I need to send back the errors to the view…

NOTE: What I did–>

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Index([ModelBinder(typeof(CustomModelBinder))] ICollection<CustomFields> Fields)
{
//code here...
}

Custom Model binder gets values from form collection and transforms in into the correct type- is this correct? The best way to do this? I get the feeling I overcomplicated things…

public class CustomModelBinder : IModelBinder
{
 public object BindModel(ControllerContext controllerContext, 
 ModelBindingContext    bindingContext)
 {

  var fields = new List<CustomFields>();

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

  foreach (string _key in formCollection)
  {
    if (_key.Contains("_RequestVerificationToken"))
         break;

    fields.Add(new CustomFields { Name = _key, 
    Value = formCollection.GetValue(_key).AttemptedValue });
  }
  return fields;
 }
}

Answer 1

Everything is perfect until step 3 where you mention foreach loops in a view. That’s where I would stop and use editor templates instead. So replace the loop in your view by:

<%= Html.EditorForModel() %>

and inside the corresponding editor template which will be rendered for each element of the model collection (~/Views/Shared/EditorTemplates/CustomFields.ascx):

<div class="editor-label">
   <%= Html.LabelFor(x => x.Name) %>
</div>
<div class="editor-field">
   <%= Html.TextBoxFor(x => x.Name) %>
</div>
<div class="editor-field">
   <%= Html.TextBoxFor(x => x.Value) %>
</div>
<div class="editor-field">
   <%= Html.TextBoxFor(x => x.Description) %>
</div>
<div class="editor-field">
   <%= Html.TextBoxFor(x => x.FieldType) %>
</div>

then simply:

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Index(IEnumerable<CustomFields> fields)
{
    //code here...
}

No need of any model binders. The editor template will take care of generating proper names for the input fields so that they are correctly bound.