YII2 Basic version of the MVC section

First, Model1, what is the model

• Models are part of the MVC pattern and are objects that represent business data, rules, and logic
• Model classes can be defined by inheriting Yii\base\model or its subclasses (ActiveRecord), and the base class Yii\base\model supports many useful features
• The model class is also the base class for more advanced models such as active record activity records.

2. Yii\base\model supports the following practical features:

Properties : Performance of business data that can be accessed like a normal class property or array (e.g. Public $name)
Property Label : Specifies the label that the property displays (for example: Models\contactform class,function Attributelabels () {} method, which defines the attribute tag)

 Public function Attributelabels () {  return  [  //  All Verifycode properties are displayed as verification in the page Code//  All of the name properties are displayed as "name" two characters in the same polygon );}　　

3, Block assignment value: Support one step to assign values to many attributes;

$model->load (Yii::$app# Use the Load () method for block assignment, $app->request->post () Get all the data submitted by the front desk.

4, validation rules: ensure that data data conforms to the stated validation rules (for example, in the Models\contactform class, method defined inside)

 public   function   rules () { return   [[[ ' name ', ' email ', ' subject ', ' body '], ' required '], //
      name, email, subject and body are required fields  [' Name ', ' Integer '], //  name must be an integer  [' name ', ' compare ', ' comparevalue ' =>30, ' Operator ' = ' >= '], //  name >=30  [' Email ', ' email ', //  Email must be a legitimate email address  [' Verifycode ', ' captcha '], //  Verification code must be filled in correctly  Span style= "COLOR: #000000" >];}   

Validation uses the yii\base\model::validate () method to trigger data validation, and if data validation fails, the yii\base\model::haserrors () property to true ,
You can use Yii \base\model::geterrors () to view error details. e.g:

 <? PHP   $model  = new   Entryform ();   $model , name = ' Carroll ' ;   $model -e-mail = ' wrong ' ;  if  ( $model -> validate ()) { //  validation successful }else  { //  validation failed//using $ Error = GetErrors (), $model; Var_dump ($errors); Get error details. }

• Yii\base\model for the parent class of the normal model class and is not related to the data table
• Yii\base\activerecord is used for the parent class of the normal model class and is related to the data table
• Yii\base\activerecord also inherits Yii\base\model, but adds database processing

5. The association between table and table ( Many-to-one or single -story, e.g. articles corresponding to article status, using HasOne () )

/* * *  establish the link between the article class and the article state class, establish this connection, the equivalent of the original post class is a property status0, this attribute value is the object of the article State class *  get state name can be used: $thePost Status0->name to get */publicfunction  getStatus0 () {  return$ this//  Poststatus::classname is the table name of the article Status table, [' id ' = ' status '] is the condition of the Association }

(One -to-many , for example articles corresponding to article comments, using hasmany () )

    /* *     * Post class has a commets attribute, this property is an array, the array is composed of comment objects     * Get comments using: $Post-and comments to get, but it is an object array, if you want to access a specific object, You need to use foreach to     traverse *    /publicfunction  getcomments ()    {         return$this->hasmany (Comment::classname (), [' post_id ' = ' id ']);    }

Second, View1, layout files

• A layout is a special view that represents the public part of multiple views, using views/layouts/main.php by default

2. How to create a layout

• Layouts are also views, which can be created as normal views
• Layouts are stored by default under @app \view\layouts

3. How to change the layout

• @app \view\layouts\main.php layout file is used by default
• Replace the layout in the entire class : public $layout = ' DCR ';
• Replace The layout of one page: Add $this, layout = ' DCR ' in the method;
• If a page doesn't need any layout, just set the $this in the method ->layout=false;

4. layout file data

• Two predefined variables $this and $content
• As with $this in the view,$this to an instance of Yii\web\view
• $content is the result of the controller rendering , the results of each page are different.

5. Structure of layout file

<?php$this->beginpage ()?>//called at the beginning of the layout $this point to Yii\web\view to manage and render this view file to identify the beginning of an HTML file$this-Header()?>//called at the head tag to identify the location of the HTML file header$this->beginbody ()?>//called at the beginning of the body to identify the starting position of the body part of the HTML file<?php$this->endbody ()?>//called at the beginning of the body to identify the end position of the body part of the HTML file</body>$this->endpage ()?>//called at the end of the layout to identify the end of an HTML file

6, using <?=html::encode ($variable)?> can prevent malicious JavaScript XSS (cross-site scripting) attack, is to use Htmlspecialchars () to convert the pre-defined characters to HTML entities

Htmlspecialchars ($content, Ent_quotes | Ent_substitute, ' UTF-8 ', true);

• Ent_quotes-encode double and single quotation marks
• Ent_substitute-Replaces the invalid encoding with a specified Unicode substitution character u+fffd (UTF-8) or & #FFFD; character, instead of returning an empty string.

7, the application of render in view:

$this->render (' _form ', [    　　$model,?>

• _form is a file in the same directory that is designed to display the form
• Model is an array of objects queried from the database

Three, Controller1, controller

• The c part of the MVC structure
• Inherited from Yii\base\controller.
• Specifically, you get the data you need from the model object, and then call the view template file to render the data, and then generate the output response information

2. Composition

• The controller mainly has the movement composition
• Actions are methods in the Controller class
• One action corresponds to a page

3. Render ()

View method: View the render () method from all yii\web\controller\ methods in the class reference manual
public string render ($view, $params =[])

• $view refers to the view name
• $params is the data passed to the view
• Returns a string, which is the result of rendering good
• The exception that is thrown when the view or file is not saved

4, the method of the controller

• Yii uses the action prefix to differentiate between common methods and operations. The action behind the action is mapped to the ID of the action
• If the method name consists of multiple words, the view name is concatenated with hyphens, for example:

 Public function Actionsayhello ($message= ' Hello ') {    return$this Render (' Say-hello ', [' message ' = +$message]);

5, Yii\web\request::p Ost () method is responsible for collecting user-submitted data

 Public functionActionentry () {$model=NewEntryform; if($model->load (Yii::$app->request->post ()) &&$model-Validate ()) {return $this->render (' entry-confirm ', [' model ' =$model]); }Else{return $this->render (' entry ', [' model ' =$model]); }}

• Yii:: $app Represents an application instance, a globally accessible singleton that provides components for specific functions such as request, response, DB , etc.

Note: This article for the author (44106-kangaroo) after reading Wei teach you to learn Yii2.0 video after the note, if reproduced please indicate the source: http://www.cnblogs.com/chrdai/p/8004737.html

YII2 Basic version of the MVC section