javascript - 我使用 Bootstrap 多选的下拉列表未填充

Question

我正在尝试使用引导 javascript 和 css 文件创建多选下拉列表。不幸的是，我动态创建的选项集(使用 AJAX)似乎没有填充列表。

我知道它一定与多选功能有关，因为当我将其设置为单选下拉菜单时，它效果很好。

不知道是否与这个函数的调用时间有关。该列表不会在文档准备好时调用，而是在 ajax 调用成功之后调用。

这是代码:

function Participants(sid){
    console.log(sid);
    $('#participants').empty()
     $('#participants').append("<option>Loading......</option>");
    $.ajax({ 
           method:"POST",
           url:"participants_dropdown.php?sid="+sid,
           contentType:"application/json; charset=utf-8",
           dataType:"json",
           success: function(data){
           console.log('success')
           $('#participants').empty();
           $('#participants').append("<option value='0'>---Select Participants---</option>");
           $.each(data, function(i, item){
                  $('#participants').append('<option value="'+data[i].facility_id+'">Call-Sign: '+data[i].call_sign+' - Operator: '+data[i].operator+' - Primary Programming: '+data[i].primary_programming+'</option>');
                  });
           },
           complete: function(){
           }
           });
    $('#participants').multiselect('destroy');
    $('#participants').multiselect();
}

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/css/bootstrap-multiselect.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/js/bootstrap-multiselect.js"></script>





<div class="col-md-4">
<h3><span>2) Select Market Participants</span></h3>
<select id="participants" multiple class="form-control">
</select>
</div>


<!---sample JSON
[{"operator":"Nexstar Media Group Inc","owner":"Mission Broadcasting Inc","call_sign":"KRBC-TV","facility_id":"306","primary_programming":"NBC"},{"operator":"Nexstar Media Group Inc","owner":"Nexstar Media Group Inc","call_sign":"KTAB-TV","facility_id":"59988","primary_programming":"CBS"},{"operator":"Prime Time Christian Broadcasting Incorporated","owner":"Prime Time Christian Broadcasting Incorporated","call_sign":"KPCB-DT","facility_id":"77452","primary_programming":"REL"},{"operator":"Sinclair Broadcast Group Inc","owner":"Sinclair Broadcast Group Inc","call_sign":"KTXS-TV","facility_id":"308","primary_programming":"ABC"},{"operator":"TEGNA Inc","owner":"TEGNA Inc","call_sign":"KXVA","facility_id":"62293","primary_programming":"FOX"}]--->

任何指导将不胜感激。我尝试过类似帖子中建议的各种解决方案，但没有成功。

Answer 1

在您的 Participant 函数中，您有一个 ajax 调用。因为这是一个异步调用，所以您需要在成功片段内移动销毁并创建多选:

function Participants(sid){
     console.log(sid);
     $('#participants').empty()
     $('#participants').append("<option>Loading......</option>");
     $.ajax({
         method:"POST",
         url:"participants_dropdown.php?sid="+sid,
         contentType:"application/json; charset=utf-8",
         dataType:"json",
         success: function(data){
             console.log('success')
             $('#participants').multiselect('destroy');
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ HERE
             $('#participants').empty();
             $('#participants').append("<option value='0'>---Select Participants---</option>");
             $.each(data, function(i, item){
                 $('#participants').append('<option value="'+data[i].facility_id+'">Call-Sign: '+data[i].call_sign+' - Operator: '+data[i].operator+' - Primary Programming: '+data[i].primary_programming+'</option>');
          });
             $('#participants').multiselect();
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ HERE
         },
         complete: function(){
         }
     });
 }

代码片段(按钮模拟ajax调用):

$('#participants').empty()
$('#participants').append("<option>Loading......</option>");
$('#participants').multiselect();


$('#btn').on('click', function(e) {
    var data = [{"operator":"Nexstar Media Group Inc","owner":"Mission Broadcasting Inc","call_sign":"KRBC-TV","facility_id":"306","primary_programming":"NBC"},{"operator":"Nexstar Media Group Inc","owner":"Nexstar Media Group Inc","call_sign":"KTAB-TV","facility_id":"59988","primary_programming":"CBS"},{"operator":"Prime Time Christian Broadcasting Incorporated","owner":"Prime Time Christian Broadcasting Incorporated","call_sign":"KPCB-DT","facility_id":"77452","primary_programming":"REL"},{"operator":"Sinclair Broadcast Group Inc","owner":"Sinclair Broadcast Group Inc","call_sign":"KTXS-TV","facility_id":"308","primary_programming":"ABC"},{"operator":"TEGNA Inc","owner":"TEGNA Inc","call_sign":"KXVA","facility_id":"62293","primary_programming":"FOX"}];
    $('#participants').multiselect('destroy');
    $('#participants').empty();
    $('#participants').append("<option value='0'>---Select Participants---</option>");
    $.each(data, function(i, item){
        $('#participants').append('<option value="'+data[i].facility_id+'">Call-Sign: '+data[i].call_sign+' - Operator: '+data[i].operator+' - Primary Programming: '+data[i].primary_programming+'</option>');
    });
    $('#participants').multiselect();
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/css/bootstrap-multiselect.css">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.15/js/bootstrap-multiselect.js"></script>

<div class="col-md-4">
    <h3><span>2) Select Market Participants</span></h3>
    <select id="participants" multiple class="form-control">
    </select>
    <button id="btn" class="btn btn-primary">Click Me</button>
</div>