Bootstrap 4 Ajax加载模式

Question

I am migrating from BS3 to BS4.1

In my apps I do use ajax loaded modals.

In layout I have

<div class="modal fade" id="myModalToFillInfo" tabindex="-1" role="dialog" aria-labelledby="myModalToFillInfoLabel" aria-hidden="true">
</div>

Then button

<button type="button" class="btn btn-primary" title="Informace o uživateli" onclick="showUserDetail(@u.Id)" data-toggle="modal" data-target="#myModalToFillInfo">
   <i class="fas fa-info" aria-hidden="true"></i>
</button>

and simple JS func

showUserDetail = function (id) {
    $.get('/Uzivatel/ModalUserInfo/' + id,
        function (data) {
            $('#myModalToFillInfo').html(data);
        });
}

Func load for example this

<div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>

So its makes a example modal togather. Thanks to data-toggle and target it auto opens the modal.

Problem is that close buttons dosen't work.

Same code was working in BS3.

Doesn anyone know how to solve this?