使用Javascript/jQuery动态填充下拉列表

Question

在ASP .NET MVC Razor视图中,我有一个下拉列表,如下所示:

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

DeviceModelList只是一个SelectList.

如何根据客户端操作(如按钮单击或使用Javascript/jQuery/Ajax的其他下拉选项)动态填充DeviceModelList？

Answer 1

您可以将此下拉列表外部化为部分:

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

然后在你的主视图中将它包含在一些容器中:

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

然后你可以有一个控制器动作,它采取一些参数,并根据它的值,它呈现这个部分:

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

现在最后一部分是发送AJAX请求以在发生某些事件时刷新下拉列表.例如,当某些其他ddl的值发生更改时(或其他内容,按钮单击或其他内容):

$(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控制器操作只会返回一些包含新键/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
                        })
                    );
                });
            }
        });
    });
});

最后你的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' }
    });
}

对于类似的示例,您可以查看以下答案.