我有一个页面,其中只有形式存在,我想把形式放在屏幕的中心。

<div class="container">
  <div class="row justify-content-center align-items-center">
    <form>
      <div class="form-group">
        <label for="formGroupExampleInput">Example label</label>
        <input type="text" class="form-control" id="formGroupExampleInput" placeholder="Example input">
      </div>
      <div class="form-group">
        <label for="formGroupExampleInput2">Another label</label>
        <input type="text" class="form-control" id="formGroupExampleInput2" placeholder="Another input">
      </div>
    </form>   
  </div>  
</div>

justify-content-center使表单水平对齐,但我不知道如何垂直对齐。我尝试使用align-items-center和align-self-center,但它不起作用。

我错过了什么?

DEMO


当前回答

我来到这里是因为我遇到了Bootstrap 4网格系统和Angular *ngFor循环的问题。我通过对实现ngFor的div应用一个col justify-content-center类来修复它:

<div class="row" style="border:1px solid red;">
  <div class="col d-flex justify-content-center">
    <button mat-raised-button>text</button>
  </div>
  <div *ngFor="let text of buttonText" class="col d-flex justify-content-center">
    <button mat-raised-button>text</button>
  </div>
</div>

结果是:

其他回答

从bootstrap v5.0开始:

<div class="position-absolute top-50 start-50 translate-middle">
   centred
</div>

我被要求在容器流体内垂直中心显示形式,所以我开发了自己的代码。

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
    <style>
       .container-fluid
       {
            display: table-cell;
            height: 100vh;
            width: 100vw !important;
            vertical-align: middle;
            border:1px solid black;
       }
    </style>
</head>

<body>
    <div class="container-fluid">
        <div class="row">
            <div class="col-8 offset-2">
                <div class="card shadow">
                    <div class="card-header bg-danger text-white">
                        <h2>Login</h2>
                    </div>

                    <div class="card-body">
                        <form action="">
                            <div class="form-group row">
                                <label for="txtemail" class="col-form-label col-sm-2">Email</label>
                                <div class="col-sm-10">
                                    <input type="email" name="txtemail" id="txtemail" class="form-control" required />
                                </div>
                            </div>
                            <div class="form-group row">
                                <label for="txtpassword" class="col-form-label col-sm-2">Password</label>
                                <div class="col-sm-10">
                                    <input type="password" name="txtpassword" id="txtpassword" class="form-control"
                                        required />
                                </div>
                            </div>
                            <div class="form-group">
                                <button class="btn btn-danger btn-block">Login</button>
                                <button class="btn btn-warning btn-block">clear all</button>
                            </div>
                        </form>
                    </div>
                </div>
            </div>
        </div>
        <script src="js/jquery.js"></script>
        <script src="js/popper.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
</body>

</html>

引导的方式

超文本标记语言

 <div class="row top-row">
        <div class="col center-text">
            <H1>Center Text Horizantally and vertically</H1>
        </div>
</div>

自定义CSS

  .top-row{
        height: 300px; //It's important to set height 
    }
  .center-text{
       display: flex;
       align-items: center;
       justify-content: center;
    }

Flexbox可以帮助您。信息在这里

<div class="d-flex flex-row justify-content-center align-items-center" style="height: 100px;">
    <div class="p-2">
     1
    </div>
    <div class="p-2">
     2
    </div>
</div>

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet"/> <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <div class="col-12 border border-info"> <div class="d-flex justify-content-center align-items-center" style="height: 100px"> <a href="#" class="btn btn-dark">Transfer</a> <a href="#" class="btn btn-dark mr-2 ml-2">Replenish</a> <a href="#" class="btn btn-dark mr-3">Account Details</a> </div> </div>