javascript - jquery select2 v4 - 选择选择元素上的默认选项

Question

我正在使用select2 v4我将 select2 连接到 <select>使用ajax方法的元素。一切正常，除了我不能在加载时默认选定的值。

examples page说:

If you need to provide default selections, you just need to include an option for each selection that contains the value and text that should be displayed.

在此代码中，我想将值默认为“foo”:

标记:

<label class="input">
  <select aria-hidden="true" tabindex="-1" 
    class="form-control user-school-select select2-hidden-accessible" 
    name="user[school_id]" id="user_school_id">
    <option selected="selected" value="1">foo</option>
  </select>
  <span style="width: 372px;" dir="ltr" 
    class="select2 select2-container select2-container--default">
    <span class="selection">
      <span aria-labelledby="select2-user_school_id-container" 
        tabindex="0" class="select2-selection select2-selection--single" 
        role="combobox" aria-autocomplete="list" aria-haspopup="true" 
        aria-expanded="false">
          <span title="foo" id="select2-user_school_id-container" 
            class="select2-selection__rendered"></span>
          <span class="select2-selection__arrow" role="presentation">
            <b role="presentation"></b></span></span></span>
 <span class="dropdown-wrapper" aria-hidden="true"></span></span></span>
</label>

此标记是由我的 Rails View (users/edit.html.erb) 生成的:

<%= label_tag nil, nil, :class => "input" do %>
  <% if @user.school_id %>
    <%= f.select :school_id, 
                 options_for_select({ @user.user_school => @user.school_id }, @user.school_id ), {}, 
                 { class: "form-control user-school-select" } %>
  <% else %>
    <%= f.select :school_id, {}, {},
                 {class: "form-control user-school-select"} %>
  <% end %>
<% end %>

users.js.erb 中的 JavaScript:

$(document).ready(function() {
  $(".user-school-select").select2({
    ajax: {
        url: "/schools",
        dataType: 'json',
        delay: 250,
        data: function (params) {
            return {
                q: params.term, // search term
                page: params.page
            };
        },
        processResults: function (data, page) {
            return {
                results: data
            };
        },
        cache: true
    },
    escapeMarkup: function (markup) { return markup; }, 
    minimumInputLength: 2,
    templateResult: formatSchool,
    templateSelection: formatSchoolSelection
  }); 
});  

function formatSchool (school) {
  var markup = '<div class="clearfix">' +
        '<div class="col-sm-1">' +
        (school.logo_url ? '<img src="' + school.logo_url + '" style="max-width: 100%" />' : "") +
        '</div>' +
        '<div class="col-sm-10">' +
        '<div class="clearfix">' +
        '<div class="col-sm-9">' + school.name + '</div>' +
        '</div>';
  markup += '</div></div>';
  return markup;
} 

function formatSchoolSelection (school) {
  return school.name;
}

我可以在 select2 生成的标记中看到该跨度有 title属性填充了我的值，但实际的跨度文本为空:

<span class="selection">
  <span aria-labelledby="select2-user_school_id-container" tabindex="0" 
    class="select2-selection select2-selection--single" 
    role="combobox" aria-autocomplete="list" aria-haspopup="true" 
    aria-expanded="false">
    <span title="foo" id="select2-user_school_id-container" 
      class="select2-selection__rendered"></span>
    <span class="select2-selection__arrow" role="presentation">
      <b role="presentation"></b></span></span></span>

我还使用 initSelection 尝试了其他已弃用的方法无济于事:

$(".user-school-select").select2({
    ajax: {
        url: "/schools",
        dataType: 'json',
        delay: 250,
        data: function (params) {
            return {
                q: params.term, // search term
                page: params.page
            };
        },
        processResults: function (data, page) {
            return {
                results: data
            };
        },
        cache: true
    },
    escapeMarkup: function (markup) { return markup; }, // let our custom formatter work
    minimumInputLength: 2,
    templateResult: formatSchool,
    templateSelection: formatSchoolSelection,
    initSelection : function (element, callback) {
        var data = {"id":"1","text":'foo'};
        callback(data);
    }
});
$(".user-school-select").select2("data", {"id": 1, "text": "foo"});

我也尝试添加此行后也无济于事:

$(".user-school-select").select2("val", "1");

我看过很多类似问题的答案，但它们不适用于我的场景。我想是因为我正在使用 select2 v4 。我读过的大多数其他答案都说您需要使用 initSelection与 val 结合- 但那些其他示例始终使用 <input>元素而不是 <select> 。我在最新的文档中确实注意到 initSelection已折旧，取而代之的是 current DataAdapter的方法应该使用，但我不知道如何将其应用到上面的代码中？

Answer 1

这不是正确的答案，但我必须应用一种解决方法 - 通过删除 templateSelection 方法来解决问题。但这不是一个好的解决方案，因为我想要 templateSelection 方法的好处。我暂时不用它就可以了。

$(document).ready(function() {
  $(".user-school-select").select2({
    ajax: {
        url: "/schools",
        dataType: 'json',
        delay: 250,
        data: function (params) {
            return {
                q: params.term, // search term
                page: params.page
            };
        },
        processResults: function (data, page) {
            return {
                results: data
            };
        },
        cache: true
    },
    escapeMarkup: function (markup) { return markup; }, 
    minimumInputLength: 2,
    templateResult: formatSchool/*,
    templateSelection: formatSchoolSelection*/
  }); 
});