Hi All,

In my view I have:
Code:
<tr>
                            <td>@Html.LabelFor(model => model.Group, null, null, null)</td>
                            <td>@Html.EditorFor(model => model.Group)</td>
                            <td>&nbsp;</td>    
                        </tr>
                        <tr>
                            <td>@Html.LabelFor(x => x.VehicleTypeId, null, null, null)</td>
                            <td>@Html.DropDownListFor(x => x.VehicleTypeId, new SelectList(Model.VehicleTypes, "Id", "Description"), "-- Select --")</td>
                            <td>&nbsp;</td>
                        </tr>
when the view initially shows my dropdown is empty. when the user places a value in group then this will cause a partial update to happen:

Code:
 $("#Group").change(function () {
        partialUpdate();
    });

function partialUpdate() {
        var polId = $("#PolicyZoneID").attr("value");
        var secId = $("#SectionID").attr("value");
        var riskId = $("#RiskID").attr("value");
        var riskTypeId = $("#RiskTypeID").attr("value");
        var group = $("#Group").attr("value");

        var jSonData = '{ "policyZoneId" : "' + polId +
                         '","sectionId" : "' + secId +
                         '","riskId" : "' + riskId +
                         '","riskTypeId" : "' + riskTypeId +
                         '","group" : "' + group + '"}';

        $.ajax({
            url: window.rootDir + 'RoadRisk/PrivateCarsReload',
            type: 'POST',
            data: jSonData,
            dataType: 'json',
            contentType: 'application/json; charset=utf-8',
            success: function (data) {
                //remove existing contents from the dropdown
               //and update with new contents. 
               

            },
            error: function (data) {
                alert(data);
            }
        });
        
    }
my controller has:
Code:
[HttpPost]
        public JsonResult PrivateCarsReload(int policyZoneId, int sectionId, int riskId, int riskTypeId, int group)
        {
            return Json(RoadRiskService.UpdatePrivateCarsFromAjax(policyZoneId, sectionId, riskId, riskTypeId, group), JsonRequestBehavior.DenyGet);
        }
this will return a struct in the form:
Code:
public struct PrivateCarsRiskJsonResults
    {
        public IEnumerable<PointsSelectListItemWrapper> VehicleTypes;
    }
where:
Code:
public class PointsSelectListItemWrapper
    {
        public Int64 Id { get; set; }
        public string Description { get; set; }
        public Int32 Points { get; set; }
        public bool Selected { get; set; }
        public Int32? MinGroup { get; set; }
        public Int32? MaxGroup { get; set; }
    }
How do I populate my dropdown list and how do I keep it in sync on the model? Thanks