Nullable Datetime field not getting rendered in Store (Ext JS)

[sa_kurup]

<ext:Store ID="StoreSample" runat="server" RemotePaging="true" RemoteSort="true" AutoLoad="true"
ShowWarningOnFailure="false" >
<Proxy>
<ext:HttpProxy Url="~/Samples/OpenEdit/GetSampleList" Json="true">
</ext:HttpProxy>
</Proxy>
<Reader>
<ext:JsonReader IDProperty="Id" Root="data">
<Fields>
<ext:RecordField Name="Id" Type="Int">
</ext:RecordField>
<ext:RecordField Name="SampleDescription" Mapping="Description">
</ext:RecordField>
<ext:RecordField Name="SamplestartDate" Mapping="StartDate" Type="Date">
</ext:RecordField>
<ext:RecordField Name="SampleEndDate" Mapping="EndDate" Type="Date" >
</ext:RecordField>
</Fields>
</ext:JsonReader>
</ext:Store>

In this store the fields SampleStartDate and SampleEndDate are of type Nullabe Datetime (Datetime?) in the model. In controller i am getting value for every field and i am converting this to StoreResult in the function GetSampleList. But in store i am always getting the value as 'undefined' in these two fields. But if i change the datatype from Datetime? to DateTime the in model i am getting all the values in store.Can any one help me to get the nullable datetime value in store?

[scottmartin]

Please try the following code and make any adjustments as needed to simulate your problem:

Ext.application({
    name: 'test',
    launch: function () {
        Ext.define('Company', {
            extend: 'Ext.data.Model',
            fields: [{
                name: 'id',
                type: 'int'
            }, {
                name: 'todate',
                type: 'date'
            }]
        });

        Ext.define('Companies', {
            model: 'Company',
            extend: 'Ext.data.Store'
        });

        var store = Ext.create('Companies');

        store.loadRawData([{
            "id": 1,
            "todate": "2011-08-08"
        }, {
            "id": 2,
            "todate": null
        }, {
            "id": 3,
            "todate": "2011-08-09"
        }]);

        var grid = Ext.create('Ext.grid.Panel', {
            store: store,
            columns: [{
                header: 'Id',
                dataIndex: 'id'
            }, {
                header: 'To',
                dataIndex: 'todate',
                xtype: 'datecolumn'
            }],
            columnLines: true,
            width: 600,
            height: 300,
            title: 'GRID',
            renderTo: Ext.getBody()
        });
    }
});​

Regards,
Scott.