发布于 2015-08-01 11:21:03 | 387 次阅读 | 评论: 0 | 来源: 网络整理
The primary way of using forms in Yii is through yiiwidgetsActiveForm. This approach should be preferred when the form is based upon a model. Additionally, there are some useful methods in yiihelpersHtml that are typically used for adding buttons and help text to any form.
A form, that is displayed on the client side, will in most cases have a corresponding model which is used to validate its input on the server side (Check the Validating Input section for more details on validation). When creating model-based forms, the first step is to define the model itself. The model can be either based upon an Active Record class, representing some data from the database, or a generic Model class (extending from yiibaseModel) to capture arbitrary input, for example a login form. In the following example we show, how a generic Model is used for a login form:
<?php
class LoginForm extends yiibaseModel
{
public $username;
public $password;
public function rules()
{
return [
// define validation rules here
];
}
}
In the controller, we will pass an instance of that model to the view, wherein the yiiwidgetsActiveForm widget is used to display the form:
<?php
use yiihelpersHtml;
use yiiwidgetsActiveForm;
$form = ActiveForm::begin([
'id' => 'login-form',
'options' => ['class' => 'form-horizontal'],
]) ?>
<?= $form->field($model, 'username') ?>
<?= $form->field($model, 'password')->passwordInput() ?>
<div class="form-group">
<div class="col-lg-offset-1 col-lg-11">
<?= Html::submitButton('Login', ['class' => 'btn btn-primary']) ?>
</div>
</div>
<?php ActiveForm::end() ?>
In the above code, yiiwidgetsActiveForm::begin() not only creates a form instance, but also marks the beginning of the form. All of the content placed between yiiwidgetsActiveForm::begin() and yiiwidgetsActiveForm::end() will be wrapped within the HTML <form> tag. As with any widget, you can specify some options as to how the widget should be configured by passing an array to the begin method. In this case, an extra CSS class and identifying ID are passed to be used in the opening <form> tag. For all available options, please refer to the API documentation of yiiwidgetsActiveForm.
In order to create a form element in the form, along with the element's label, and any applicable JavaScript validation, the yiiwidgetsActiveForm::field() method is called, which returns an instance of yiiwidgetsActiveField. When the result of this method is echoed directly, the result is a regular (text) input. To customize the output, you can chain additional methods of yiiwidgetsActiveField to this call:
// a password input
<?= $form->field($model, 'password')->passwordInput() ?>
// adding a hint and a customized label
<?= $form->field($model, 'username')->textInput()->hint('Please enter your name')->label('Name') ?>
// creating a HTML5 email input element
<?= $form->field($model, 'email')->input('email') ?>
This will create all the <label>, <input> and other tags according to the yiiwidgetsActiveField::$template defined by the form field. The name of the input field is determined automatically from the model's yiibaseModel::formName() and the attribute's name. For example, the name for the input field for the username attribute in the above example will be LoginForm[username]. This naming rule will result in an array of all attributes for the login form to be available in $_POST['LoginForm'] on the server side.
Specifying the attribute of the model can be done in more sophisticated ways. For example when an attribute may take an array value when uploading multiple files or selecting multiple items you may specify it by appending [] to the attribute name:
// allow multiple files to be uploaded:
echo $form->field($model, 'uploadFile[]')->fileInput(['multiple'=>'multiple']);
// allow multiple items to be checked:
echo $form->field($model, 'items[]')->checkboxList(['a' => 'Item A', 'b' => 'Item B', 'c' => 'Item C']);
Additional HTML tags can be added to the form using plain HTML or using the methods from the yiihelpersHtml-helper class like it is done in the above example with yiihelpersHtml::submitButton().
Tip: If you are using Twitter Bootstrap CSS in your application you may want to use yiibootstrapActiveForm instead of yiiwidgetsActiveForm, which is an extension of the ActiveForm class that adds some additional styling that works well with the bootstrap CSS framework.
Tip: in order to style required fields with asterisk you can use the following CSS:
div.required label:after { content: " *"; color: red; }
The next section Validating Input handles the validation of the submitted form data on the server side as well as ajax- and client side validation.
To read about more complex usage of forms, you may want to check out the following sections: