问Asp.net核心MVC jquery自动完成返回空白数据行

EN

@section Scripts{

    <link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
    <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>

    <script src="~/lib/Scripts/jquery-3.4.1.js"></script>
    <script src="~/lib/Scripts/jquery-ui.min.js"></script>
<script>

$("#searchInput").autocomplete({
source: function (request, response) {
$.ajax({
url: '@Url.Action("GetSearchValue", "Requests")',
dataType: "json",
data: { search: $("#searchInput").val() },
success: function (data) {
response($.map(data, function (item) {
return { label: item.NameString};
}));
},
error: function (xhr, status, error) {
alert("Error");
}
});
}
});

</script>
}

    [HttpGet]
    public async Task<IActionResult> GetSearchValue(string search)
    {
        var allsearch = _context.Requests.Where(x => x.NameString.ToLower().Contains(search)).Select(x => new Requests
        {
            NameString = x.NameString,
        }).ToList();
        return Ok(allsearch);
    }