To what mvc object do I bind this kind of javascript array?

Question

I am populating an array with an [int,bool]:

$.each(ownedChecked, function (key, val) {
    /*code to set id as int and paintedTrue as bool*/
    ownedIDs.push([id,paintedTrue]);
});

I create a var that will be stringified:

var saveData = { OwnedListEntryIDs:ownedIDs };

//send data
$.ajax({
    url: '/ListEntry/OwnedModels',
    type: 'POST',
    contentType: 'application/json; charset=utf-8',
    data: JSON.stringify(saveData),
    success: function (data) { alert('Update success: ' + data); },
    failure: function (data) { alert('Update failed: ' + data); }
});

Here is the ViewModel:

public class OwnedPaintedSave
{
    //collection contains a ListEntryID and a bool indicating whether it is painted or not
    public Dictionary<int,bool> OwnedListEntryIDs { get; set; }
}

Once in the controller method, ModelState.Isvalid passes and code gets to the foreach loop, but models is always NULL:

[HttpPost]
public JsonResult OwnedModels(OwnedPaintedSave models)
{
    if (ModelState.IsValid)
    {
        foreach (var id in models.OwnedListEntryIDs)
        { }
    }
}

I tried setting traditional:true in the $.ajax method, but same issue. I'm guessing the Dictionary in the ViewModel is not what I need to bind to, but I'm not sure what it should be. Thanks for any help.

Chris M · Accepted Answer · 2012-05-28 19:53:28Z

1

I gave the OwnedPaintedSave object two int[] properties, one for OwnedIDs and one for PaintedIDs.

answered May 28, 2012 at 19:53

Chris M

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Comments

Simon · Accepted Answer · 2012-05-28 07:09:21Z

0

I think the problem lies in your controller. You are passing var saveData = { OwnedListEntryIDs:ownedIDs }; (essentially a Dictionary<int, bool> - yes?) as your data but the parameter in the action result is of type OwnedPaintedSave

I think if you change your controller parameter to Dictionary<int, bool> ownedListEntryIDs and don't stringify the javascript object, the framework is clever enough to serialize and deserialize your object. So you would have this...

var saveData = { OwnedListEntryIDs:ownedIDs };

//send data
$.ajax({
    url: '/ListEntry/OwnedModels',
    type: 'POST',
    contentType: 'application/json; charset=utf-8',
    data: saveData,
    success: function (data) { alert('Update success: ' + data); },
    failure: function (data) { alert('Update failed: ' + data); }
});

And then this in your controller...

[HttpPost]
public JsonResult OwnedModels(Dictionary<int, bool> ownedListEntryIDs)
{
    if (ModelState.IsValid)
    {
        foreach (var id in ownedListEntryIDs)
        { }
    }
}

answered May 28, 2012 at 7:09

Simon

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2 Comments

Chris M Over a year ago

Correct me if I am wrong, but accepting an OwnedPaintedSave object with properties of the types I'm passing in is referred to as a ViewModel or DataTransferObject. I've used this pattern in other places, but this is the first time I want a property to contain a Dictionary-style parameter. In any case, I decided to work around this by defining the OwnedPaintedSave object to have two properties: int[] OnwedIDs and int[] PaintedIDs, and let the Controller method decide if painted is true. Thanks for the assistance! -C

Simon Over a year ago

Correct, but you were not passing the view model back to the controller. You were passing the property inside the view model to the controller. thinking about it, if you just changed the name of the JS var from saveData to models (the name of the parameter in your controller), it should work.

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