Earlier in the course, you learnt how data types like string and bool are used to represent basic data and perform basic operations.

But what if you need to go one step further than this and work with more complex data in your C# application?

For instance, you may be writing a program that manages botanical gardens and you need to track all the plants.

The gardens may have a certain number of plants with unique names and characteristics.

It wouldn't be viable to track that many separate variables and methods using basic data types.

In this case, you would want to define your own custom data type called Plant, using it like any other data type in your program.

With C#, this Plant custom data type will be defined with a class and each instance of this type as an object.

This approach to defining classes and creating objects from them is covered in the first step to this module and is key to you being able to manage real-world data in your C# applications.

This step will also introduce you to auto-assigning properties and defining default values to them, always assisting you with writing code that is cleaner and easier to maintain.

When developing object-oriented applications, you've already seen how you can use classes to model business data, but what about any actions, such as validation, or calculations that may need to be performed on the data to fulfil business and behavioral rules?

How can you keep these rules associated with the entity itself?

The answer is encapsulation, a technique used to bundle code into a single unit, where you can determine the scope of each piece of data.

In this instance, it can help to wrap that business functionality inside the class itself.

By doing this, you keep the business rules associated with the entity alongside the data, which means the business rules are able to enforce the validity of the data and prevent the entity being processed in ways which aren't allowed.

When you're dealing with business entities, it's often the case that there is certain data that must be provided at the time an object is instantiated for the entity to make any sense.

This module also considers situations where only some of the properties of a business object need to be specified by the client at object instantiation.

You'll therefore need to learn how to set default property values in the constructor and some alternative ways for managing this.

In addition, every class will typically host a set of methods or functions that allow instances of the class to manipulate their internal state and implement the business and behavioral rules.

You'll learn how to declare and call methods, and what happens when you try and add multiple methods with the same name.

There are situations where client code should only be able to manipulate an object's data indirectly, so controlling access to data is an important part of component or class design.

For example, when dealing with a bank account's balance, client code should be able to retrieve the balance but not directly set it.

Any changes made to the balance would need to be logged, so there's an audit trail.

Consequently, the bank account class should support deposit and withdrawal methods which, when invoked by the client code, would write to the logs and adjust the balance accordingly.

As usual, at the end of the module, you'll be offered the opportunity to put what you've learnt into practice in the lab and coding challenge.

Take your time to cover everything and make sure you understand it before moving on.

Using data classes | C# F |

About