Visualforce Interview Questions

 Visualforce is new markup language which is introduced by Salesforce, and by using this language, we can even render the standard styles of the salesforce. We can at present utilize HTML here in Visualforce. Each Visualforce tag dependably starts with the “apex” namespace. The Visual Markup language and the business logic are used in the designing part of the page.

 No, it isn’t generally fundamental. You can utilize standard controllers and VF part labels to achieve a considerable amount. The apex ends up essential when you require either a custom data set or custom activities to be accessible from the page.

AJAX is principally used for the partial page updates in the Visualforce. In s-controls, AJAX toolbox was a soap customer that gave you access to the force.com Web Service API.

 To delete the Users Data go to Setup, next go to Administration Setup, then to Data Management and then visit Mass Delete Record, from that point select the items like Account, Lead and so on and in criteria choose the client’s name and then delete all records of that client identified with specific protest.

 The VisualForce controller usually defines a whole instruction set that basically indicates what all can happen when the client communicates with various parts accessible on VisualForce pages. These segments might be links, buttons, or some other activity thing. There are three mainstream kinds of Visual Force Controllers in Salesforce. These are Controller Extensions, Standard Controller and the Custom Controller.

 For this reason, you have to get to client details page and just enable the ‘development mode’ choice there to utilize the VisualForce Editor.

 They can deal with numerous pages and state over each page that isn’t conceivable to manage by other easier controllers in VisualForce. The VisualForce controller mainly distinguishes the entire set of the guidelines that basically indicate what all can happen when the client cooperates with various parts accessible on VisualForce pages.

These segments might be links, buttons, or some other activity thing. There are three well-known sorts of Visual Force Controllers in Salesforce.

 To forestall information to be spared in see express, a transient keyword is utilized as a part of VisualForce. It ought to be used for transitory factors as it were.

Essentially, you have to characterize the segment of the page that you wish to refresh (regularly with a board of sorts), and afterward distinguish the event that will cause the page to refresh. The technique changes if the area being updated is the same as the one taking care of the event. It likewise relies upon if you are merely handling something on the server, or on the off chance that you require the UI to change.

 Both consider custom code to be utilized, taking into consideration custom data sets and custom activities. The extension mainly uses the current information and activities inside a standard or custom controller.

The Custom controllers must contain all data and activities that should be executed by the page. The extension that mainly expands the standard controller takes into account all the pages which usually use those extensions to be used as a part of the standard button overrides, custom buttons,  and over declarative features.

  Given below are the three binding types:

1. Data binding basically refers to the set of data in the controller.
2. Action binding usually refers to the action techniques in the controller.
3. Component binding simple refers to other Visualforce parts
4. What do you mean by static resources?

The Static resources are another storage type in Salesforce mainly intended for use in Visualforce pages. They are approaches to store pictures, flash documents, templates, and other web assets on the Salesforce servers that could usually be cached for the better page execution.

 If you needed to execute any business logic just like how to render a part and many other things than the component controllers are required for the custom components.

 With the Properties help, you may permit making standard getters or setters naturally and still, they are accessible for customization. The real advantage of Properties is that you don’t need to compose monotonous code for quite a long time and besides you don’t need to read the clutters while looking into the code.

 A VisualForce page is built mainly with the basic HTML components, controllers, and optional style components on Force.com platform. Like HTML, VisualForce can be coordinated with any standard web technology, JavaScript system or a database for building up the feature-rich animated UI. There is one of a kind URL for each VisualForce page, which is rendered over the server.

 The VisualForce has global keywords like component, User, URL, current page and so forth, to get to different qualities from parts on the page, from client object or URL or current page fields. To get to a value from each source, we have various global keywords.
Different global keywords include:

1. URL
2. Client
3. PROFILE
4. Resource
5. Component
6. Current page
7. Page reference and so on..

1. actionStatus: used to show begin and stop statuses of AJAX requests.
2. actionSupport: used for calling the second component when the event happens to the primary component.
3. actionPoller: like actionSupport, yet an event depends on the timer rather than a client activity.
4. actionFunction: offers help for invoking the controller activity from the JavaScript code utilizing an AJAX request by characterizing another JavaScript work.
5. actionRegion: used to divide which parts of the page the server ought to reprocess.

 In Salesforce you can connect the standard and the custom objects record in a detailed list. The Object relationship review mainly does it. Different kinds of relationships can be made keeping in mind the end goal to interface the particular business cases with specific clients. It is conceivable to make custom relationship on the object and characterize different relationship types.

1. Tabula report: In this report, the total is shown in the tabular format.
2. Matrix report: A top to bottom report wherein the there is both column based and line based grouping.
3. Summary report:  It is a kind of report in which grouping is on the basis of the column.
4. Joined report: A joining of at least two reports into one.

It is exceptionally valuable and essential idea presented by the salesforce as of late. It enables to the software engineer to expand the usefulness of existing custom controller or the standard controller.

A Visualforce can have a single standard controller or Custom controller, however, numerous controller extensions.

We can state that the custom extension is the supporter of custom or the standard controller.

Example of the above case:

If there is one controller that is written and utilized by the various visualforce pages and one of them needs some additional logic. At that point, instead of writing that particular logic to the controller class (Which is utilized by numerous visualforce pages) we can make a controller extension and apply to that page as it were.

Mainly, using tabs, links, inline frames and buttons you can do so.

 
Visualforce pages that usually contain a form part additionally include the hidden form field and encrypted field that exemplifies the page’s view state. This view state is consequently created, and as the name recommends, it holds the page state – the state that incorporates the parts, field values, and the controller state.

Best Practices to lessen the view state size

1. Minimize the number of forms on the page. Utilize apex:actionRegion as opposed to utilizing at least two forms.
2. Refine your SOQL just to retrieve the information required by the page.
3. All private and public data members in the Custom, Standard, and Controller extensions are saved.
4. Mark any of the Apex variables that is not important to the view state as Transient. (The transient variables are not merely passed to see state and consequently not put away in View State)
5. Create wizards with as few pages as could be expected under the circumstances
6. Use outputLink parts rather than commandLink or commandButton segments where conceivable as they don’t should be settled in shape.

 The Governor Limits are basically runtime limits upheld by Apex runtime engine. Since Apex keeps running in a mutual, multitenant condition, Apex runtime engine entirely upholds various cutoff points to guarantee that code does not monopolize shared assets. 

Different limit types that Apex generally authorizes includes the things such as resources like database resources, memory,  number of script proclamations to stay away from unbounded circles, and number of records being prepared. If code surpasses a breaking point, the related governer issues a special runtime case.

 Yes, the properties are useful in the controllers. The Properties can naturally make standard getters and setters while as yet taking into account their customizations. They spare you from both written work the repetitive code and reading the messiness while code reviewing.

 Any content that can be rendered in a program (HTML, JavaScript, and so forth.).