对象不支持属性或方法“自动完成”

@model IEnumerable<ModelClass.DhoniRegistry>
@using (@Html.BeginForm())
{
    <b> Dhoni Name  </b>
    @Html.TextBox("SearchTerm", null, new { id = "txtSearch" })
    <input type="submit" value="Search" />
}    
<link href="~/Content/jquery-ui.min.css" rel="stylesheet" />
<link href="~/Content/jquery-ui.structure.min.css" rel="stylesheet" />
<link href="~/Content/jquery-ui.theme.min.css" rel="stylesheet" />
<script src="~/Scripts/external/jquery/jquery.js"></script>
<script src="~/Scripts/jquery-ui.min.js"></script>
<script src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>
<script type="text/javascript">
    $(function ()
    {
        $("#txtSearch").autocomplete({ source: '@Url.Action("ASDhoniName")' });
    });
</script>

控制器

public JsonResult ASDhoniName(string SearchTerm)
{
    DhoniRegistryBusinessSer dhoniBisSer = new DhoniRegistryBusinessSer();
    List<string> dhoniReg;
    dhoniReg = dhoniBisSer.ListDhoniRegistry().Where(x => x.DhoniName.StartsWith(SearchTerm))
        .Select(y => y.DhoniName).ToList();
    return Json(dhoniReg,JsonRequestBehavior.AllowGet);
}