Knockout with MVC3: Knockout model won't send collection data?

ANSWER: Replacing this line:

self.identifiers.push(new Identifier(self.identifierToAdd(), self.selectedIdentifierTypeValue()));

      

        
        
        
      

    

With this line:

self.identifiers.push({ Key: self.identifierToAdd(), Value: self.selectedIdentifierTypeValue()});

      

        
        
        
      

    

Mail requests now send collection data correctly. However, this does not address the fact that the MVC action is not getting it, but the question is already big enough.

I cannot get the data from my knockout model's collection property into my MVC model when published to an action. If I alert ko.toJSON

my identifiers()

property at the bottom it displays all the data correctly, but when I try to send that data using a normal postback (the action just takes the EquipmentCreateModel below) it looks like this:

The ids are empty and when I look at the ModelState error for ids it says it is cannot convert String to Dictionary<Guid, string>

. What am I doing wrong? I thought MVC3 would automatically convert JSON to objects if possible, how was it done with properties BuildingCode

and Room

?

Also why does my string data in the above snapshot have escaped quotes?

edits: If I look at the post data, the IDs appear as an empty array ( identifiers: [{}]

). I tried jsoning ids in the save method like:

self.identifiers = ko.toJSON(self.identifiers());

      

        
        
        
      

    

This leads to the fact that the request data will not be empty and looks like this:

identifiers:"[{\"Value\":\"sdfsd\",\"Key\":\"4554f477-5a58-4e81-a6b9-7fc24d081def\"}]"

      

        
        
        
      

    

However, the same problem occurs when I debug the activity. I also tried to find out the whole model (as described in knockoutjs submit with the ko.utils.postJson question ):

ko.utils.postJson($("form")[0], ko.toJSON(self));

      

        
        
        
      

    

But this gives a .NET error that says Operation is not valid due to the current state of the object.

that, looking at the request data, it looks like JSON-ified twice, because each letter or character is its own value in the HttpCollection, and this is because only .NET allows 1000 max by default ( 'Operation invalid due to an error in the current state of the object during postback ).

Using the $ .ajax method to send the data, everything works fine:

 $.ajax({
            url: location.href, 
            type: "POST",
            data: ko.toJSON(viewModel),
            datatype: "json",
            contentType: "application/json charset=utf-8",
            success: function (data) { alert("success"); }, 
            error: function (data) { alert("error"); }
        });

      

        
        
        
      

    

But for other reasons, I cannot use the $ .ajax method for this, so I need it to work in regular mail. Why can I have the toJSON

whole viewModel in ajax request and it works, but in normal postback it breaks it up and when I don't, all quotes are escaped in the sent JSON.

Here is my ViewModel:

public class EquipmentCreateModel
{
//used to populate form drop downs
public ICollection<Building> Buildings { get; set; }
public ICollection<IdentifierType> IdentifierTypes { get; set; }

[Required]
[Display(Name = "Building")]
public string BuildingCode { get; set; }

[Required]
public string Room { get; set; }

[Required]
[Range(1, 100, ErrorMessage = "You must add at least one identifier.")]
public int IdentifiersCount { get; set; } //used as a hidden field to validate the list
public string IdentifierValue { get; set; } //used only for knockout viewmodel binding

public IDictionary<Guid, string> Identifiers { get; set; }
}

      

        
        
        
      

    

Then my knockout script / ViewModel:

<script type="text/javascript">
// Class to represent an identifier
function Identifier(value, identifierType) {
    var self = this;
    self.Value = ko.observable(value);
    self.Key = ko.observable(identifierType);
}

// Overall viewmodel for this screen, along with initial state
function AutoclaveCreateViewModel() {
    var self = this;

    //MVC properties
    self.BuildingCode = ko.observable();
    self.room = ko.observable("55");
    self.identifiers = ko.observableArray();
    self.identiferTypes = @Html.Raw(Json.Encode(Model.IdentifierTypes));
    self.identifiersCount = ko.observable();


    //ko-only properties
    self.selectedIdentifierTypeValue = ko.observable();
    self.identifierToAdd = ko.observable("");

    //functionality
    self.addIdentifier = function() {
        if ((self.identifierToAdd() != "") && (self.identifiers.indexOf(self.identifierToAdd()) < 0)) // Prevent blanks and duplicates
        {
            self.identifiers.push(new Identifier(self.identifierToAdd(), self.selectedIdentifierTypeValue()));
            alert(ko.toJSON(self.identifiers()));
        }
        self.identifierToAdd(""); // Clear the text box
    };

    self.removeIdentifier = function (identifier) {
        self.identifiers.remove(identifier);
        alert(JSON.stringify(self.identifiers()));
    };

    self.save = function(form) {
        self.identifiersCount = self.identifiers().length;
        ko.utils.postJson($("form")[0], self);
    };
}
    var viewModel = new EquipmentCreateViewModel();
    ko.applyBindings(viewModel);
    $.validator.unobtrusive.parse("#equipmentCreation");      
    $("#equipmentCreation").data("validator").settings.submitHandler = viewModel.save;

      

        
        
        
      

    

View:

@using (Html.BeginForm("Create", "Equipment", FormMethod.Post, new { id="equipmentCreation"}))
{
@Html.ValidationSummary(true)
<fieldset>
    <legend>Location</legend>
    <div class="editor-label">
        @Html.LabelFor(model => model.BuildingCode)
    </div>
    <div class="editor-field">
        @Html.DropDownListFor(model => model.BuildingCode, new SelectList(Model.Buildings, "BuildingCode", "BuildingName", "1091"), "-- Select a Building --", new { data_bind = "value:BuildingCode"})
        @Html.ValidationMessageFor(model => model.BuildingCode)
    </div>
    <div class="editor-label">
        @Html.LabelFor(model => model.Room)
    </div>
    <div class="editor-field">
        @Html.TextBoxFor(model => model.Room, new { @class = "inline width-7", data_bind="value:room"})
        @Html.ValidationMessageFor(model => model.Room)
    </div>
</fieldset>
<fieldset>
    <legend>Identifiers</legend>
    <p>Designate any unique properties for identifying this autoclave.</p>
    <div class="editor-field">
        Add Identifier
        @Html.DropDownList("identifiers-drop-down", new SelectList(Model.IdentifierTypes, "Id", "Name"), new { data_bind = "value:selectedIdentifierTypeValue"})
        @Html.TextBox("identifier-value", null, new { @class = "inline width-15", data_bind = "value:identifierToAdd, valueUpdate: 'afterkeydown'" })
        <button type="submit" class="add-button" data-bind="enable: identifierToAdd().length > 0, click: addIdentifier">Add</button>
    </div>

    <div class="editor-field">
        <table>
            <thead>
                <tr>
                    <th>Identifier Type</th>
                    <th>Value</th>
                    <th></th>
                </tr>
            </thead>
            <!-- ko if: identifiers().length > 0 -->
            <tbody data-bind="foreach: identifiers">

                <tr>
                    <td>
                        <select data-bind="options: $root.identiferTypes, 
                        optionsText: 'Name', optionsValue: 'Id', value: Key">
                        </select>
                    </td>
                    <td><input type="text" data-bind="value: Value"/></td>
                    <td><a href="#" class="ui-icon ui-icon-closethick" data-bind="click: $root.removeIdentifier">Remove</a></td>
                </tr>


            </tbody>
            <!-- /ko -->
            <!-- ko if: identifiers().length < 1 -->
            <tbody>
                <tr>    
                    <td colspan="3"> No identifiers added.</td>
                </tr>
            </tbody>
            <!-- /ko -->
        </table>
        @Html.HiddenFor(x => x.IdentifiersCount, new { data_bind = "value:identifiers().length" })<span data-bind="text:identifiers"></span>
        @Html.ValidationMessageFor(x => x.IdentifiersCount)
    </div>    
</fieldset>
<p>
    <input type="submit" value="Create" />
</p>
}