您可以将此下拉列表局部化：

@model MyViewModel
@Html.DropDownListFor(model => model.SelectedDeviceModel, Model.DeviceModelList)

然后在主视图中将其包含在某个容器中：

@model MyViewModel
...
<div id="ddlcontainer">
    @Html.Partial("Foo", Model)
</div>
...

那么您可能会有一个控制器动作，该动作需要一些参数，并根据其值呈现此部分参数：

public ActionResult Foo(string someValue)
{
    MyViewModel model = ... go ahead and fill your view model
    return PartialView(model);
}

现在，最后一部分是在发生某些事件时发送AJAX请求以刷新下拉列表。例如，当某些其他ddl的值发生更改（或其他更改，单击按钮或其他操作）时：

$(function() {
    $('#SomeOtherDdlId').change(function() {
        // when the selection of some other drop down changes 
        // get the new value
        var value = $(this).val();

        // and send it as AJAX request to the newly created action
        $.ajax({
            url: '@Url.Action("foo")',
            type: 'POST',
            data: { someValue: value },
            success: function(result) {
                // when the AJAX succeeds refresh the ddl container with
                // the partial HTML returned by the Foo controller action
                $('#ddlcontainer').html(result);
            }
        });
    });
});

另一种可能性是使用JSON。您的Foo控制器操作将仅返回一些包含新键/值集合的Json对象，并且在AJAX请求的成功回调中，您将刷新下拉列表。在这种情况下，您无需将其外部化为单独的部分。例如：

$(function() {
    $('#SomeOtherDdlId').change(function() {
        // when the selection of some other drop down changes 
        // get the new value
        var value = $(this).val();

        // and send it as AJAX request to the newly created action
        $.ajax({
            url: '@Url.Action("foo")',
            type: 'POST',
            data: { someValue: value },
            success: function(result) {
                // when the AJAX succeeds refresh the dropdown list with 
                // the JSON values returned from the controller action
                var selectedDeviceModel = $('#SelectedDeviceModel');
                selectedDeviceModel.empty();
                $.each(result, function(index, item) {
                    selectedDeviceModel.append(
                        $('<option/>', {
                            value: item.value,
                            text: item.text
                        })
                    );
                });
            }
        });
    });
});

最后，您的Foo控制器动作将返回Json：

public ActionResult Foo(string someValue)
{
    return Json(new[] {
        new { value = '1', text = 'text 1' },
        new { value = '2', text = 'text 2' },
        new { value = '3', text = 'text 3' }
    });
}