The Controller is one of the most important parts of AngularJS's MVC design. It is wise to keep the controllers light, but you still need to know about controllers and how to use them properly.
This tutorial will show you how to utilize controllers in your AngularJS apps in numerous ways. Discussing the model, leveraging services, nesting controllers, and different approaches to link the Controller to the View will be included.
What are AngularJS Controllers?
This JavaScript methodology utilizes the $scope object with AngularJS to maintain the application's state and functions.
Using the controller function, $scope may be enhanced with properties and methods that can be applied to HTML components.
When the ng-controller directive is applied to an HTML element, a controller for the data and children of that element may be defined. A controller's $scope objects have attributes, and the following HTML sample displays the values of those properties for the Controller.
MyController is the Controller's name in the previous example, where ng-controller="myController" is given to a div> element. The expression message is included inside the div element. We need to develop an application module to create "myController." If you want to know more details, you can take a best angular course for beginners.
Example: AngularJS Controller
<!DOCTYPE html> <html > <head> <title>AngualrJS Controller</title> <script src="~/Scripts/angular.js"></script> </head> <body ng-app="myNgApp">
<div ng-controller="myController"> {{message}} </div><script> var ngApp = angular.module('myNgApp', []); ngApp.controller('myController', function ($scope) { $scope.message = "Hello World!";}); </script></body>
</html> An application's controllers, services, and other components are kept out of the module's global scope. (The module will be discussed in further detail in the following section.) The controller in angularjs () method takes two parameters: a controller name and a controller function, which must be sent in after the module has been created.
The AngularJS framework will inject the $scope argument into the controller method.
Controller Basics
The view manages the visual layout, whereas the model handles most business logic. However, controllers utilize the javascript system in AngularJS, while plain conceptual models do not; controllers commonly employ services to assist build up a model or even to manage interactions from the view.
Controller Methods
The following controllers in angular extensions and custom controller methods may be used in visual force markup:
Action Methods
User actions, such as clicking a button or hovering across an area of the page, trigger action methods, which conduct logic or navigation. Using the! Syntax in the act parameter from one of these tags, you may invoke action methods from page markup:
Command buttons and command links may be created using apex:commandLink and apex:actionPoller, respectively, to perform a specific command. Every so often, the action apex:actionSupport> is called. An action (such as "onclick" or "onmouseover") on another component, and then performs an action
<apex:actionFunction> new JavaScript method for calling action apex:page> in the page object executes code as soon as the page has loaded
The action argument of the apex:commandButton> tag, for angularjs controller example, calls the Controller's save function in the sample page from Build a Custom Controller. In Defining Action Methods, we look at several further instances of action methods.
Methods That Return Values
A controller's getter methods return the controller's values. A getter method is required for every Value a controller calculates and displays on a page, along with any Boolean variables. For instance, the controller provides a getAccount function in the sample page from Build a Custom Controller.
This allows the page markup to access the account member variables in the controller class using the '!' notation in the page's HTML code. This syntax is used to register and login, and dot notation shows the account name on the apex:inputField> tag. There must always be a method called get Variable for getter methods.
The Setter Method
A controller receives data given by the user through setter methods in the page HTML. A controller's setter methods are automatically run before any response methods.
For example, if you want to search for leads, you may use the following markup. When the user hits Go! An SOSL query is sent using the search string entered into the related Controller's getter and setter methods.
Controller Defined Within a Module
A JavaScript function Object () { [native code] } function defines the controller. In an AngularJS application, the Controller governs and functions as the brain for the View.
The ng-controller directive is used to connect the Controller to the DOM. Only business logic should be included in controllers. In our Angular module, we are going to add a Controller. For more updates, you can choose the web design and development course.
Connecting Controllers to Views
- Right-click the Controllers folder in Solution Explorer and choose Add Controller.
- Select MVC 5 Controllers – Empty from the drop-down menu and click the Add button.
- ItemController should be given a name.
- This is how your Object Controller will look.
- Select Add View from the context menu when right-clicking on Index Action Method.
Working with Dependencies
It is a software development technique that allows components to be provided their dependencies rather than hard coding them into the component itself. "Dependency Injection" As a result, a component no longer has to worry about trying to track the source of dependence. Making components reusable, manageable, and re-testable is also an advantage.
When it comes to Dependency Injection, AngularJS is unmatched. Injecting dependencies into one another is easy since it offers the following essential components.
A JavaScript object called Value is needed to provide values to the Controller during the config phase.
Returning an object is the primary purpose of a factory. When a service or control needs it, it generates Value. Calculation and return of the Value are often accomplished via a factory function.
All of the functionality of the service is contained in one JavaScript object. The service () method is used to define it, and the controllers are injected with it.
AngularJS uses a Provider to construct services, factories, etc., during the config stage of the development process. To construct MathService, the following script is required. The get() function of the Provider factory method is used to return a value/service/factory.
Variables are used to transmit values because values cannot be utilized in the configuration phase.
Nested Controllers
This JavaScript object is generated by using the function Object() { [native code] } of an existing JavaScript object. Properties and functions may be included in a controller. An AngularJS application's controllers are used to manage the application's data.
With the assistance of examples, we'll learn about the nested controllers of AngularJS and how they work. To develop an AngularJS controller, we first need to establish an application module.
Description
The Controller () function adds a gamepad to an already-created module.
The Controller's name is sent as the first argument to the Controller () function.
$scope is the second argument of the function. The AngularJS framework provides the $scope object to each Controller.
The $scope object in the controller function may have various attributes and methods added to it.
To access a property of the Controller or maintain data in an Html tag, you must use the ng-controller directive to identify the Controller you are working with.
We have given the controller "myCtrl" additional attributes in the above code to demonstrate. String, integer, object, array, and function are all examples of attributes that may be assigned to a controller.
It is possible to nest controllers with AngularJS. An HTML element that is a child of another HTML element with a different controller is referred to as a "child" controller. Note that although a child controller may access the methods and properties of its parent controller, the parent controller can't get its hands on a child controller's properties and methods.
External Controllers
Suppose your microcontroller (MCU) does not have enough CAN FD channels. In that case, our additional CAN controller is a cost-effective and versatile option for adding CAN or CAN Fully Duplex (CAN FD) functionality to your MCU. You may also add CAN FD capabilities to an existing model without having to replace your system MCU using our products.
Therefore, you do not have to re-design your whole system to take advantage of the increased data rates and data-byte message extension offered by the May FD protocol. You can also utilize our external FD controller solutions. Development time and risk are reduced because of our developer tools, software, and sample code ecosystem.
External CAN and CAN FD Controllers
With one of these devices, automotive and industrial MCUs may get CAN functionality or more CAN FD channels.
Key Advantages
- Adaptable to any microcontroller (MCU)
- CAN 2.0B and can FD networks are supported.
- May FD can be added to the existing design simply.
- Channel expansion for a microcontroller (MCU)
- Compliant with ISO 11898-1:2015 & ISO 11898-2
- A wide working voltage range of 2.7 to 5.5 volts is supported.
- Many different bundles are on offer.
- -40°C to +150°C high-temperature operation
External CAN Controllers + Transceiver
One of the advantages of these devices is that they can be readily added to an MCU since they have both the Controller and the transmitter in a single package.
Key Benefits:
- Reducing the number of application components
- CAN 2.0 can FD networks are supported.
- Streaming speeds of up to 8Mbps
- Low-standby current (typically 10 A).
- SPI clock speed of up to 17 MHz
- A broad working voltage range of 2.7 to 5.5 volts is supported.
- 28-pin SSOP & 28-pin QFN packages are available.
- -40°C to +150°C high-temperature operation
Testing Controllers
Controller tests focus on the Controller alone, whereas integration tests act as though the user is navigating the app via a browser window, touching every layer in the stack. Controller tests are fundamentally the same, except they are more challenging to create and time-consuming to implement.
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Conclusion
That JavaScript methodology utilizes the $scope object with AngularJS to maintain the user's data and behaviour. Add properties and behaviours to the $scope object in a control function so that the data or actions may be appended or attached to HTML elements. Choose the KnowledgeHut’s best angular course for beginners to get more details.
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