如果什么都没有 selected，我怎么给 Bootstrap select 一个正常的高度？

Question

我在我的页面中使用 bootstrap select，我需要它在页面加载时默认为空 (and value="")（这是必填字段，因此当用户提交表单时，验证如果它是空的，则会出现消息）。

它确实有效，但它看起来 weird/odd/too 平淡：

这就是期望的结果：

我使用此属性使 select 看起来是空的：data-none-selected-text="" 它实际上看起来是空的但太平了。

如果我删除那个属性，我会得到这个 Nothing selected 我不想要的占位符：

如何使设计保持一致并保持相同的尺寸，无论某些东西是否被 select 编辑？

body {
  background-color: lightblue !important;
}

<head>
  <!-- Bootstrap CSS -->
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-EVSTQN3/azprG1Anm3QDgpJLIm9Nao0Yz1ztcQTwFspd3yD65VohhpuuCOmLASjC" crossorigin="anonymous">
  <!-- Bootstrap Select CSS -->
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-select@1.13.14/dist/css/bootstrap-select.min.css">
</head>

<body>
  <div class="container-fluid">
    <div class="row mt-3">
      <div class="col-sm">
        Project Manager <span style="color:red;">*</span>
      </div>

      <div class="col-sm">
        <select class="selectpicker show-tick w-100" data-none-selected-text="" multiple data-max-options="2" aria-label="Project Manager" required>
          <option value="Michal Jackson">Michael Jackson</option>
          <option value="Michael Jordan">Michael Jordan</option>
          <option value="Luke Skywalker">Luke Skywalker</option>
          <option value="Rafael Nadal">Rafael Nadal</option>
          <option value="Cristiano Ronaldo">Cristiano Ronaldo</option>
          <option value="Albert Einstein">Albert Einstein</option>
        </select>
      </div>
    </div>
  </div>

  <!-- Popper.js 5.0.2 JS -->
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/2.9.2/umd/popper.min.js"></script>
  <!-- Bootstrap 5.0.2 JS -->
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-MrcW6ZMFYlzcLA8Nl+NtUVF0sA7MsXsP1UyJoMp4YLEuNSfAP+JcXn/tWtIaxVXM" crossorigin="anonymous"></script>
  <!-- jQuery CDN -->
  <script src="https://code.jquery.com/jquery-3.6.0.js" integrity="sha256-H+K7U5CnXl1h5ywQfKtSj8PCmoN9aaq30gDh27Xc0jk=" crossorigin="anonymous"></script>
  <!-- Bootstrap Select JS BETA VERSION, UPDATE TO A STABLE VERSION COMPATIBLE WITH BS5 ONCE IT IS RELEASED-->
  <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.14.0-beta2/js/bootstrap-select.min.js"></script>
</body>

Answer 1

您可以覆盖默认 bootstrap class 并为这种情况创建一个例外。

.dropdown-toggle {
   height: 50px;
 }

Answer 2

如果您真的不想使用占位符文本，只需使用空白 HTML space ( ) 作为 data-none-selected-text 或 placeholder 属性值。这两种方法都会导致 select 框保持标准高度，其中没有可见文本。

body {
  background-color: lightblue !important;
}

<head>
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-EVSTQN3/azprG1Anm3QDgpJLIm9Nao0Yz1ztcQTwFspd3yD65VohhpuuCOmLASjC" crossorigin="anonymous">
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-select@1.13.14/dist/css/bootstrap-select.min.css">
</head>

<body>
  <div class="container-fluid">
    <div class="row mt-3">
      <div class="col-sm">
        Data Attribute Example <span style="color:red;">*</span>
      </div>

      <div class="col-sm">
        <select class="selectpicker show-tick w-100" data-none-selected-text="&nbsp;" multiple data-max-options="2" aria-label="Project Manager" required>
          <option value="Michal Jackson">Michael Jackson</option>
          <option value="Michael Jordan">Michael Jordan</option>
          <option value="Luke Skywalker">Luke Skywalker</option>
          <option value="Rafael Nadal">Rafael Nadal</option>
          <option value="Cristiano Ronaldo">Cristiano Ronaldo</option>
          <option value="Albert Einstein">Albert Einstein</option>
        </select>
      </div>
    </div>

    <div class="row mt-3">
      <div class="col-sm">
        Placeholder Example <span style="color:red;">*</span>
      </div>

      <div class="col-sm">
        <select class="selectpicker show-tick w-100" placeholder="&nbsp;" multiple data-max-options="2" aria-label="Project Manager" required>
          <option value="Michal Jackson">Michael Jackson</option>
          <option value="Michael Jordan">Michael Jordan</option>
          <option value="Luke Skywalker">Luke Skywalker</option>
          <option value="Rafael Nadal">Rafael Nadal</option>
          <option value="Cristiano Ronaldo">Cristiano Ronaldo</option>
          <option value="Albert Einstein">Albert Einstein</option>
        </select>
      </div>
    </div>
  </div>

  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/2.9.2/umd/popper.min.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/js/bootstrap.bundle.min.js" integrity="sha384-MrcW6ZMFYlzcLA8Nl+NtUVF0sA7MsXsP1UyJoMp4YLEuNSfAP+JcXn/tWtIaxVXM" crossorigin="anonymous"></script>
  <script src="https://code.jquery.com/jquery-3.6.0.js" integrity="sha256-H+K7U5CnXl1h5ywQfKtSj8PCmoN9aaq30gDh27Xc0jk=" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.14.0-beta2/js/bootstrap-select.min.js"></script>
</body>

如果什么都没有 selected，我怎么给 Bootstrap select 一个正常的高度？

How can I give Bootstrap select a normal height if there is nothing selected?

html

twitter-bootstrap

bootstrap-select