Ajax call doesn't pass string to controller

Question

I am trying to pass a string to an IActionResult function in an asp.net core 3.1 controller.

Ajax:

 $(function () {
        $('#ddlUsers').change(function () {
            $.ajax({
                url: '@Url.Action("GetUserInfoPartial", "UserInfo")',
                method: 'POST',
                data: { userId: 'test' },
                contentType: 'application/json',
                dataType: 'html'
            }).done(function (r) {
                $('#partialID').html(r);
            });
        });
    });

C#:

[HttpPost]
public IActionResult GetUserInfoPartial(string userId)
{         
     return PartialView("_UserPartial", userId);
}

Breakpoints in GetUserInfoPartial are hit, but userId is always null. What am I missing?

Answer 1

you can remove 'application/json', and dataType: 'html' then it will work properly. $.ajax({ url: '@Url.Action("GetUserInfoPartial", "UserInfo")', method: 'POST', data: { userId: 'test' }, success: function (r) { $('#partialID').html(r); });