Unity 3D / 2D中的C＃：我是否需要为每个脚本使用Classes？

Question

A little background: I'm new to C# and Unity, but catching on very quickly. I'm also hoping this thread will not spark a debate about the merits of classes and abstract coding, as that debate is unrelated and well-worn (and unnecessarily heated); so please keep that in mind.

I'm simply wondering if every C# script in Unity is required to have a main class in any way or for any reason.

Or instead, can methods, and variables can be written outside of a class in a blank file (with namespaces) to be used in a video game?

I'm asking because, when I create a new C# script, it seems to force a class into my file and I'm afraid of breaking things.

• I hope to keep code abstraction to a minimum, and the current project I'm working on has several situations where a class is not needed, or only one instance of the class will be used. I'd like to simply avoid using classes in those cases.

Answer 1

In terms of declaring/defining variables and methods outside of any class, you can't really do that in C# . It just isn't how the language was designed (the answers to the question I linked to expand on that idea, so I won't duplicate them here).

You're not without options, though; if you have a number of variables or methods that need to be accessible from different places and don't need an object reference, you can make them static , so you won't need to instantiate the class to make use of them:

public class UtilityClass
{
    public static float GravityConstant = 3.51f;
    public static string GameName = "MyFirstGame";

    public static float CalculateProduct(float a, float b)
    {
        return a * b;
    }
}

Then, you can reference the class's methods/members by accessing it through its name:

float product = UtilityClass.CalculateProduct(6, 1.5f);

An example of where you might use this pattern is when defining mathematical formulae which aren't included in Unity's Mathf methods, and using them in multiple classes.

Additional note: Creating a new C# script through Unity's editor UI will default to declaring a class of the same name that inherits from Monobehaviour . You can alter it to remove the inheritance from Monobehaviour if you don't need any of the methods/attributes of the class, which avoids unnecessary overhead. One example for this would be with a static class that you never need to instantiate.

Answer 2

1. First of All you need to check where Methods define as offical docs stated

   " Methods are declared in a class or struct by specifying the access level such as public or private...."

   So, Method should be declare in a Class or struct and A given class should be, ideally, responsible for just one task. ( see also )

2. Your this question "Or instead, can methods, and variables can be written outside of a class in a blank file (with namespaces) to be used in a video game?" answer is hidden in the below question.

   Can there be stand alone functions in C# without a Class ? No. Make them static and put them in a static utility class if they indeed don't fit within any of your existing classes.

   You have to make a class in order to use methods or its variable either instance class or static class.

3. Am I required to use Classes for every script? Every script means you required a class. Unity Support Component Based Architectural Design and if you require any script related work then you definitely require a script component which means a class require.

4. Finally for singleton , thanks to Unity3dWiki great detail available. I think you will be feel comfortable to code and writing class if you keep in mind component based architecture of Unity3d.

5. Singleton vs Static : I will also recommend to check this: Why do you use a Singleton class if a Static class serves the purpose

Hope it will help.

[Note: If this helpful Any one can update this answer for future reference and use].

Answer 3

Yes, you are.

In C#, things like global variables and functions just do not exist. Everything must be contained in a class.

"But what should I do in order to declare some stuff that can be accessed everywhere, without creating an object?" you asked. There is something called the static modifier . You can access the methods or variables or fields or properties marked with this modifier without creating an object of that class.

You just add the word static in a method and it becomes a static method! How simple!

Let's see an example.

I have this non-static method:

public class MyClass {
    public void DoStuff () {

    }
}

I can call it like this:

var obj = new MyClass();
obj.DoStuff();

But if I modify it with static ,

public class MyClass {
    public static void DoStuff () {

    }
}

I can call it like this:

MyClass.DoStuff();

How convenient!

Note:

Please do not misuse the static modifier! Only use it when it makes sense! When? When the method is a utility method or when the method does not belong to individual objects but the class itself.