Map .NET Concepts to the Lightning Platform

Learning Objectives

After completing this unit, you’ll be able to:

• Understand which key features make up the Lightning Platform and the Apex programming language
  
• Identify similarities and differences between .NET and the Lightning Platform
  
• Use Developer Console to create your first Apex class
  
• Use Anonymous Apex to invoke a method from an Apex class
  

Follow Along with Trail Together

Want to follow along with an expert as you work through this step? Take a look at this video, part of the Trail Together series.

Meet the Lightning Platform

Seriously, after you get to know more about the Lightning Platform, you’ll appreciate it as much as we do. In this module, we’ll look at how you can relate the .NET concepts that you’re already familiar with to the Lightning Platform.

Platform Basics

First, let’s briefly go over what exactly comprises the Lightning Platform. One of the things that separates the platform from other software-as-a-service (SaaS) offerings is that it relies on a metadata-driven architecture. Everything, including the code, configuration, and apps, is specified as metadata.

As .NET developers, you’re probably already familiar with the cloud applications that run on Microsoft Azure. Well, the Lightning Platform works differently. The Lightning Platform is tightly integrated with the database. You also get all sorts of things, like user interface, security, and reporting, built right in with the platform. This integration is what lets you build apps super fast.

But!—and here’s the part that might make you feel a little weird at first—you, as the developer, have to give up some control to get that developer productivity. On the Lightning Platform, you don’t have to worry about setting up nodes or management tasks. You don’t have to worry about upgrading, tuning, or scaling anything. To be honest, you probably won’t miss all that added complexity and responsibility, because instead you can just focus on quickly building great apps.

Now we just skimmed the surface in terms of what the platform offers. If you want to dive a little deeper into the architecture, check out the Platform Basics module.

Apex Basics

Because the Lightning Platform is so tightly integrated and relies on a metadata architecture, you can accomplish an awful lot using declarative development, or what is known as “point-and-click” app building. If you are new to the Lightning Platform, we strongly suggest you check out the article about point-and-click development listed in Resources.

As a .NET developer, we know you like to code, but what you must realize is that on the Lightning Platform, code is not always needed. But it’s important to understand when code is needed and when it isn’t. You can learn more about this distinction by browsing this article on when to click and when to write code.

But enough about all that. We know you want to learn how you can program on the platform, which is where Apex comes in.

What Is Similar?

The Apex programming language is similar to one you probably already know and love—C#. Apex is saved, compiled, and executed directly on the Lightning Platform. Like C#, it’s object oriented. In this section, we’ll go over this and what else makes it similar to .NET languages.

Object-oriented Design

We figure you already grasp the concept of object-oriented design, so we’re not going to waste your time describing cookie cutters. Just know that Apex supports many of the object-oriented principles that you’re probably used to, such as encapsulation, abstraction, inheritance, and even polymorphism. In fact, the Apex language includes many language constructs you’re already familiar with, including classes, interfaces, properties, and collections.

For example, here is what an Apex class named HelloWorld would look like.

public with sharing class HelloWorld {
    public void printMessage() {
        String msg = 'Hello World';
        System.debug(msg);
    }
}

This simple HelloWorld class includes one method named printMessage that is used to simply output the message “Hello World” to the system debug log. Of course, this example is pretty simple, but we wanted you to see how very similar Apex is to C#.

The basic syntax for defining classes is:

private | public | global
[virtual | abstract][with sharing | without sharing | inherited sharing]
class ClassName [implements InterfaceNameList] [extends ClassName]
{
    // The body of the class
}

When you have time, check out Understanding Classes to learn more about how classes, objects, and interfaces work.

Data Types

Apex supports the kind of data types you would expect. There are primitive types, such as Integer, Double, Long, Date, Datetime, String, and Boolean. There is also an ID data type that is used for any valid 18-character Lightning Platform record identifier assigned by the system.

Value and reference types work the same, but in Apex, all variables are initialized to null by default. One thing to be aware of is that .NET strings are actually references even though they behave like value types, because they’re immutable. But in Apex, strings are always treated as a primitive value type.

Besides primitives, supported data types include sObjects, either as a generic sObject or a specific one, such as an Account or Contact. Remember, an sObject is just a Salesforce object. You can think of it as a table in a database. The sObject can be either a standard one that comes built in with Salesforce or a custom one that you define yourself.

Additionally, a data type can be a typed list of values, also known as an enum. But watch out, because these aren’t the same enums you’re used to working with in .NET. In Apex, you can use enums with numbers, but you can’t define what these number values are. Also, the ordinal assignment starts at zero. For example, if you had an enum like the following.

public enum myEnums {
            Enum1,
            Enum2,
            Enum3
 }

If you tried to access the ordinal value of the third enum, the value of the enumOrd variable would be 2.

Integer enumOrd = myEnums.Enum3.ordinal();

Working with Collections

.NET supports a large collection library with numerous types and extension methods. And here’s some good news. Apex has only the following three collections. Talk about simple, right?

List

A list is an ordered collection of elements that works much the same as a traditional array. However, Apex does not support arrays as collections, just lists. You can, however, use what’s known as “array notation” to reference specific items in a list using square brackets, []. For example, the following is one way to declare a variable as a list of strings:

List<String> myStrings =  new List<String>();

Alternatively, you can declare the myStrings list variable using square brackets, as in the following:

String[] myStrings = new List<String>();

Another thing you can do is declare the list and initialize its values, all in one step, such as the following.

List<String> myStrings =  new List<String> {'String1', 'String2', 'String3' };

You can also add values to the list after it has been created, such as this:

List<String> myStrings = new List<String>();
myStrings.add('String1');
myStrings.add('String2');
myStrings.add('String3');

You’ll probably create a lot of list variables in your Apex development, because the output of every SOQL query is a list. For example, you could create a list of Accounts using code such as the following:

List<Account> myAccounts = [SELECT Id, Name FROM Account];

Note that the list index always starts at zero. Accessing the name of the first account in the list would look like this:

String firstAccount = myAccounts.get(0).Name;

Alternatively, the following will work in the same way:

String firstAccount = myAccounts[0].Name;		// Uses Array Notation []

Set

A set is an unordered collection of elements that does not contain duplicates. A set is commonly used to store ID values because the values are always unique. You could then use the set as part of a WHERE clause in a SOQL query. For example, here we’re creating a set that contains two unique IDs for Accounts. We then use the set in the SOQL query to return Accounts only for those IDs.

Set<ID> accountIds = new Set<ID>{'001d000000BOaHSAA1','001d000000BOaHTAA1'};
List<Account> accounts = [SELECT Name FROM Account WHERE Id IN :accountIds];

Map

A map is a collection of key-value pairs. Each key maps to a single value. A map is useful when you need to quickly find something by a key. The key values must be unique, so you could have a map that contained ID values for the key and then mapped to an sObject. For example, you could use the following code to declare a map variable named accountMap that contains all Accounts mapped to their IDs.

Map<Id, Account> accountMap = new Map<Id, Account>([SELECT Id, Name FROM Account]);

You could then access a specific Account record using the get method and code similar to the following.

Id accId = '001d000000BOaHSAA1';
Account acc = accountMap.get(accId);

Check out the official docs to learn more about the data types that Apex supports.

ASP.NET to Visualforce

If you’re an ASP.NET web forms developer, you’ll probably feel right at home with Visualforce. There are many similarities between the two., most notably, a clear separation of the markup from the code. You also use form fields to map code to properties defined in the controller.

The bad news is that viewstate is just as much a pain with Visualforce as it is with ASP.NET due to the fact that HTTP is stateless. The good news is that there are ways around the viewstate limitations. Learn more by checking out the link in Resources.

Visualforce is a framework for rendering HTML pages using an MVC paradigm. Now before you get all excited and start thinking, “Cool, Visualforce is like ASP.NET MVC. I love MVC.”, keep in mind that comparing the two is a bit like comparing apples and pumpkins. You can use either one to render web pages, and both separate the application logic from the markup and the database model, but they do so in different ways.

To learn all about Visualforce, check out the Visualforce Basics module. For now, we just want to give you a basic idea of how it works by showing you an example. You can use the following markup code to render a simple page used to enter Contact data.

<apex:page standardController="Contact">
  <apex:form>
    <apex:pageBlock title="Edit Contact" mode="Edit">
       <apex:pageBlockButtons >
         <apex:commandButton action="{!edit}" id="editButton" value="Edit"/>
         <apex:commandButton action="{!save}" id="saveButton" value="Save"/>
         <apex:commandButton action="{!cancel}" id="cancelButton" value="Cancel"/>
       </apex:pageBlockButtons>
       <apex:pageBlockSection >
          <apex:inputField value="{!contact.lastname}" />
          <apex:inputField value="{!contact.accountId}"/>
          <apex:inputField value="{!contact.phone}"/>
       </apex:pageBlockSection>
    </apex:pageBlock>
  </apex:form>
</apex:page>

The example uses what is known as a standard controller, which is part of the Lightning Platform. It’s basically system-generated code that allows you to quickly incorporate basic CRUD functionality in your Visualforce pages. But before you start getting worried, just know that you can create your own custom controllers to add in more complex functionality. Learn all about how standard and custom controllers work in the Visualforce Basics module. The rendered version of this page looks like the following:

You probably know a bit about Lightning Components, and could be thinking, "Is Lightning like ASP.NET MVC?" The short answer is no. Lightning is a lighter weight way of delivering super fast and responsive web apps, but Lightning is a component-based framework. Learn all about it by visiting the Lightning Web Components Basics module.

What Is Different?

Now that you know a little about how Apex is similar to .NET, let’s go over some differences. For starters, unlike C#, Apex is not case sensitive.

Apex and Database are Tightly Coupled

Apex code and the Lightning Platform database are tightly coupled to the point where they are sometimes indistinguishable. Each standard or custom object in the database has a "mystical" representation via an Apex class that provides all sorts of functionality to make interacting with the database a snap. The class and its underlying object are essentially a mirror image of one another that is constantly in sync. For instance, whenever you create a new field in an object, a class member is automatically surfaced to reference the values in the database. It's also impossible to add a reference in your Apex code to a field that doesn't exist; the compiler will return an error and simply not save your code. The platform works hard to ensure these dependencies and won't let the database schema and your code become out of sync. Therefore, if you attempt to delete a custom object or a field that is referenced by Apex code, the platform will raise an error and disallow the action.

Different Design Patterns

As a .NET developer, you are probably already familiar with design patterns. However, most of those patterns don’t work on the Lightning Platform. You learn more about this in the next units when we go over execution context and trigger design, but also consider checking out the links listed in Resources regarding Apex design patterns.

What’s important to understand is that if you try to apply the same design strategies that you use in .NET to the Lightning Platform, you’ll likely encounter problems when you go to test and deploy your solutions. We suggest taking some time to learn about which design patterns work best in the Lightning Platform world before you start cranking out the code.

Unit Tests Are Required

We know you’re used to writing unit tests for your .NET applications and probably understand the benefits to using them. What is different on the Lightning Platform is that you must have 75% test coverage to deploy your Apex code to a production org.

Not only does having unit tests promote the development of robust and error-free code, but they’re vital to the stability of the platform, because all tests are run before every major release. To learn more about unit testing, see An Introduction to Apex Code Test Methods.

No Solution, Project, or Config Files

The Lightning Platform has no such thing as a solution or project file. You can create an application, but it’s not the same as creating a .NET application or assembly.

An application on the Lightning Platform is just a loose collection of components, such as tabs, reports, dashboards, and pages. Several come built in with your Salesforce org, and in a few seconds, you can create your own by walking through a point-and-click wizard. You can even purchase apps created by third-parties on what is known as the AppExchange.

All your code resides and executes in the cloud. There is also no such thing as a config file in the Lightning Platform world. Because the database is baked right in, you don’t need connection strings. And unlike ASP.NET MVC, you don’t need to configure routes. You can create custom settings in Salesforce, but these are added and managed declaratively.

A Much Smaller Class Library

The Apex class library is considerably smaller than the .NET Framework class library, so it’s easier and faster for you to come up to speed with Apex. But honestly, you might find it a bit frustrating when you try to look for comparative functionality that just doesn’t exist in Apex.

Keep in mind that the Lightning Platform is built with the idea of providing rapid application development. It’s also different than the .NET platform, so you might find yourself looking for functionality that you’re used to working with that simply doesn’t exist with the Lightning Platform. However, if you’re looking to build pixel-perfect, custom-coded applications, our Heroku Enterprise platform provides all the power and features you need.

Development Tools

More than likely you have already signed up for a free Developer Edition (DE) org. Perhaps you’ve also opened and used the online Developer Console application.

You can use Developer Console to edit and navigate source code, and it’s also helpful for debugging and troubleshooting. We’ll go over this more in a later unit, so stay tuned. If you’ve already gone through the first module about database basics, you know that you can also use Developer Console to execute SOQL and SOSL queries and view query plans. If you haven’t used Developer Console yet, don’t worry because we’ll be going through it shortly when we create an Apex class.

As a .NET developer, you're probably familiar with Visual Studio Code. You will be happy to learn that we have Salesforce Extensions for VS Code that allow you to do custom development on your local machine. The extension is closely tied to Salesforce DX, which provides a modern source-driven development experience. You can learn more about Salesforce DX from the Get Started with Salesforce DX trail.

And finally, we thought you would be interested to know about a powerful command-line interface to the Lightning Platform. If you’re one of those developers that just loves the command line, the Salesforce CLI is right up your alley.

To stay current with Salesforce’s evolution and built in support for DevOps, be sure to look into Code Builder, and DevOps Center.

Handling Security

The good news here is that in the Lightning Platform you don’t have to worry about authentication or storing passwords and database connection strings. Identity is handled by the platform. You can control access to data at many different levels, including object level, record level, and field level. Security is also handled declaratively. In many cases, security is defined and set up by a Salesforce administrator. As a developer, it’s important to be aware of how it works. Learn more by checking out the Data Security module.

What About Integration?

You can integrate with the platform in a number of ways, but you’ll probably use SOAP and REST the most. You can use them in either direction.

You can create and expose web services using the Apex programming language, as well as invoke external web services from Apex. You can also react to incoming email messages and have automated outbound messages sent when certain events occur.

If you really want to get your hands dirty, Salesforce offers both SOAP and REST APIs that provide direct access to the data in your org. Toolkits that wrap around the APIs are available, so you can use whatever language you prefer: .NET, Java, PHP, Objective C, Ruby, and JavaScript.

Numerous third-party integration applications are also available on the AppExchange. Really, just about anything is possible. You can learn more about all the integration points by completing the Apex Integration module.

Create an Apex Class

Now that you know more about how the Lightning Platform relates to the .NET platform, let’s jump right in and create an Apex class using Developer Console. The class we’ll create includes the public method sendMail. It includes a private helper method called inspectResults for inspecting the results of the email send call.

1. From Setup in your Developer org, select Your Name > Developer Console to open Developer Console.
   
2. In Developer Console, select File > New > Apex Class.
   
3. Enter EmailManager as the class name and click OK.
   
4. Delete the existing code, and insert the following snippet:
   

   public with sharing class EmailManager {
       // Public method
       public static void sendMail(String address, String subject, String body) {
           // Create an email message object
           Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
           String[] toAddresses = new String[] {address};
           mail.setToAddresses(toAddresses);
           mail.setSubject(subject);
           mail.setPlainTextBody(body);
           // Pass this email message to the built-in sendEmail method
           // of the Messaging class
           Messaging.SendEmailResult[] results = Messaging.sendEmail(
               new Messaging.SingleEmailMessage[] { mail });
           // Call a helper method to inspect the returned results.
           inspectResults(results);
       }
       // Helper method
       private static Boolean inspectResults(Messaging.SendEmailResult[] results) {
           Boolean sendResult = true;
           // sendEmail returns an array of result objects.
           // Iterate through the list to inspect results.
           // In this class, the methods send only one email,
           // so we should have only one result.
           for (Messaging.SendEmailResult res : results) {
               if (res.isSuccess()) {
                   System.debug('Email sent successfully');
               } else {
                   sendResult = false;
                   System.debug('The following errors occurred: ' + res.getErrors());
               }
           }
           return sendResult;
       }
   }

5. Press Ctrl + S to save your class.
   

This simple example doesn’t implement the required object- or field-level security. See this snippet for a quickstart.

Invoke a Method

Because we declared the public sendMail method as static, we can access it without creating an instance of the class. We can do so easily by using Anonymous Apex in the Developer Console.

1. From Setup, select Your Name > Developer Console to open Developer Console.
   
2. Select Debug > Open Execute Anonymous Window.
   
3. Delete the existing code, and insert the following snippet, substituting your own email address for the first parameter:
   EmailManager.sendMail('Your email address', 'Trailhead Tutorial', '123 body');
4. Make sure that the Open Log option is selected, and click Execute. A new tab shows you the execution log.
   
5. Select the Debug Only option so that you see only the debug statements displayed in the log. You should see a message telling you that the Email was sent successfully. You should also receive an email if you entered a valid email address.
   

Imagine if you had tried to accomplish that same task in .NET. Would it have been that easy to create a .NET application that sent emails? Come on, tell the truth.

Resources

• Understand the Salesforce Architecture
• Visual Development - When to Click Instead of Write Code
• Introducing Apex in the Apex Code Developer’s Guide
• An Introduction to View State
• Apex Design Patterns
• Integration Patterns and Practices