详解AngularJS中自定义指令的使用

飞鹰

2019-04-21

自定义指令中使用AngularJS扩展HTML的功能。自定义指令使用的“指令”的功能定义。自定义指令只是替换了它被激活的元素。引导过程中AngularJS应用程序找到了匹配的元素，并做好使用自定义指令compile()方法一次活动再处理使用基于指令的范围自定义指令link()方法的元素。 AngularJS提供支持，以下列元素的类型来创建自定义指令。

Element directives - 指令遇到时激活一个匹配的元素。
Attribute - - 指令遇到时激活一个匹配的属性。
CSS - - 指令遇到时激活匹配CSS样式。
Comment - - 指令遇到时激活匹配的注释。

了解自定义指令

定义自定义的HTML标签。

<student name="Mahesh"></student><br/>
<student name="Piyush"></student>

定义自定义指令来处理上面的自定义HTML标签。

var mainApp = angular.module("mainApp", []);

//Create a directive, first parameter is the html element to be attached.  
//We are attaching student html tag. 
//This directive will be activated as soon as any student element is encountered in html
mainApp.directive('student', function() {
  //define the directive object
  var directive = {};
  //restrict = E, signifies that directive is Element directive
  directive.restrict = 'E';
  //template replaces the complete element with its text. 
  directive.template = "Student: <b>{{student.name}}</b> , Roll No: <b>{{student.rollno}}</b>";
  //scope is used to distinguish each student element based on criteria.
  directive.scope = {
    student : "=name"
  }
  //compile is called during application initialization. AngularJS calls it once when html page is loaded.
  directive.compile = function(element, attributes) {
   element.css("border", "1px solid #cccccc");
  //linkFunction is linked with each element with scope to get the element specific data.
   var linkFunction = function($scope, element, attributes) {
     element.html("Student: <b>"+$scope.student.name +"</b> , Roll No: <b>"+$scope.student.rollno+"</b><br/>");
     element.css("background-color", "#ff00ff");
   }
   return linkFunction;
  }
  return directive;
});

定义控制器以更新范围为指令。在这里，我们使用name属性值作为子的作用域。

mainApp.controller('StudentController', function($scope) {
   $scope.Mahesh = {};
   $scope.Mahesh.name = "Mahesh Parashar";
   $scope.Mahesh.rollno = 1;

   $scope.Piyush = {};
   $scope.Piyush.name = "Piyush Parashar";
   $scope.Piyush.rollno = 2;
});

例子

<html>
<head>
  <title>Angular JS Custom Directives</title>
</head>
<body>
  <h2>AngularJS Sample Application</h2>
  <div ng-app="mainApp" ng-controller="StudentController">
 <student name="Mahesh"></student><br/>
 <student name="Piyush"></student>
  </div>
  <script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.15/angular.min.js"></script>
  <script>
   var mainApp = angular.module("mainApp", []);
  
   mainApp.directive('student', function() {
     var directive = {};
     directive.restrict = 'E';
     directive.template = "Student: <b>{{student.name}}</b> , Roll No: <b>{{student.rollno}}</b>";
     
     directive.scope = {
      student : "=name"
     }
  
     directive.compile = function(element, attributes) {
      element.css("border", "1px solid #cccccc");

      var linkFunction = function($scope, element, attributes) {
        element.html("Student: <b>"+$scope.student.name +"</b> , Roll No: <b>"+$scope.student.rollno+"</b><br/>");
        element.css("background-color", "#ff00ff");
      }

      return linkFunction;
     }

     return directive;
   });
  
   mainApp.controller('StudentController', function($scope) {
      $scope.Mahesh = {};
      $scope.Mahesh.name = "Mahesh Parashar";
      $scope.Mahesh.rollno = 1;

      $scope.Piyush = {};
      $scope.Piyush.name = "Piyush Parashar";
      $scope.Piyush.rollno = 2;
   });
   
  </script>
</body>
</html>

结果

在Web浏览器中打开textAngularJS.html。看到结果如下：

详解AngularJS中自定义指令的使用