C# Namespaces in Unity! - Intermediate Scripting Tutorial

Namespaces are like containers for classes. Their purpose is to help your organize your scripts and to avoid conflicts between scripts. You might, for example, be making tools in Unity to help you develop your application. You could keep the tools and actual application in separate namespaces so you didn't have too many unnecessary classes being suggested by autocomplete. Chances are, all of the scripts you have been writing so far have been using namespaces. At the top of C# scripts in Unity, b

y default, you'll see two lines: "using UnityEngine;", and "using System.Collections;" UnityEngine and System.Collections are both namespaces. The "using" keyword means that anything within the namespace that follows can be used in the script. Try commenting out the "using" directives at the top of the script, and you can see that autocomplete has far fewer classes that you can use. That's because classes like GameObject, Transform, RigidBody, and many more, are all in the UnityEngine namespace.

In order to put our class in a namespace, we need to surround the class with the namespace syntax. Start off with the keyword "namespace", and then the namespace's name. This can be an existing namespace, or a new one. In this case, we are gonna call our namespace "SampleNamespace". Then we have an open brace before the class, and a closed brace after the class. Since our class now belongs to SampleNamespace, we'll indent it to show belonging. There are three ways we can use the classes from a

specific namespace. We've already seen the first which is to include a "using" directive at the top of your script. The second way to access the class is to use the dot operator. For example, instead of having "using SampleNamespace;" at the top of the script, every time we wanted to reference a class from the SampleNamespace, we could type SampleNamespace, dot, and then the class. This option avoids ambiguity, but could be cumbersome, particularly with large namespace names, like SampleNamespa

ce. The last option is to put the class that you are writing into the namespace that you need access to. This is generally not recommended, unless you mean to have that class in the same namespace anyway. So long as classes are in different namespaces, they may have the same name. However, since scripts have the same name as the class contained in them, scripts must be in different folders in order to have the same class name. When using namespaces, be careful to avoid ambiguous definitions. For

example, two very common namespaces to use are "System", and "UnityEngine". These both contain a definition for a class called "Random". If you are using them both, you need to disambiguate the class by using the dot operator. Either use "System.Random" or "UnityEngine.Random". You might've noticed that the second default using directive is the "System.Collections" namespace. This illustrates that namespaces are nestable. In order to nest namespaces, simply enclose one namespace declaration wit

hin another.