（'...'）。对于带有jquery包的asp.net核心mvc，每个都不是有效函数

Question

Reposting this because I cannot find any answer that doesn't involve using Google's bundle or something else. Please tell me if I'm missing any detail so I'll add it. I have the whole jquery bundle included with VS referenced at the top of my _Layout...

@Scripts.Render("~/bundles/jquery")

Here's the BundleConfig.cs

public static void RegisterBundles(BundleCollection bundles)
        {
            bundles.Add(new ScriptBundle("~/bundles/jquery").Include(
                        "~/Scripts/jquery-{version}.js"));

            bundles.Add(new ScriptBundle("~/bundles/jqueryval").Include(
                        "~/Scripts/jquery.validate*"));

            // Use the development version of Modernizr to develop with and learn from. Then, when you're
            // ready for production, use the build tool at http://modernizr.com to pick only the tests you need.
            bundles.Add(new ScriptBundle("~/bundles/modernizr").Include(
                        "~/Scripts/modernizr-*"));

            bundles.Add(new ScriptBundle("~/bundles/bootstrap").Include(
                      "~/Scripts/bootstrap.js",
                      "~/Scripts/respond.js"));

            bundles.Add(new StyleBundle("~/Content/css").Include(
                      "~/Content/bootstrap.css",
                      "~/Content/site.css"));
        }

...but it is still telling me in this case that .each is not a function. What I'm missing or need to refer to the layout or BundleConfig? Why isn't .each a function that is a part of the jquery bundle that comes with Visual Studio 2017?

@Html.ListBox("Groups", null, new { size = 10, style = "width : 350px; max-width : 500px;", id = "grouplist" })

The whole context of my jquery:

    $('#savegroups').click(function () {
            var groupId = $('#groupId').val();
            var list = [];
            ('#grouplist').each(function (item) {
                list.append('{"groupId":"' + groupId + '","groupName":"' + item.value +'"}');
            });
            $.ajax({
                type: "POST",
                url: "/GroupCategories/EditGroups",
                data: JSON.stringify(list),
            });
   });

Error:

1:230 Uncaught TypeError: "#grouplist".each is not a function
    at HTMLInputElement.<anonymous> (1:230)
    at HTMLInputElement.dispatch (jquery:1)
    at HTMLInputElement.y.handle (jquery:1)

Answer 1

Looks like you are missing the jquery selector..

('#grouplist')

should be

$('#grouplist option')