{"id":1462,"date":"2025-03-08T22:15:27","date_gmt":"2025-03-08T14:15:27","guid":{"rendered":"http:\/\/codermr.com\/?p=1462"},"modified":"2025-03-09T18:15:12","modified_gmt":"2025-03-09T10:15:12","slug":"c%e5%9f%ba%e7%a1%80%e7%9f%a5%e8%af%86%e6%b1%87%e6%80%bb%e4%ba%8c%ef%bc%88oop%ef%bc%89%ef%bc%9a%e5%ad%97%e6%ae%b5%e3%80%81%e5%b1%9e%e6%80%a7","status":"publish","type":"post","link":"http:\/\/codermr.com\/index.php\/2025\/03\/08\/c%e5%9f%ba%e7%a1%80%e7%9f%a5%e8%af%86%e6%b1%87%e6%80%bb%e4%ba%8c%ef%bc%88oop%ef%bc%89%ef%bc%9a%e5%ad%97%e6%ae%b5%e3%80%81%e5%b1%9e%e6%80%a7\/","title":{"rendered":"C#\u57fa\u7840\u77e5\u8bc6\u6c47\u603b\u4e8c\uff08OOP\uff09\uff1a\u5b57\u6bb5\u3001\u5c5e\u6027"},"content":{"rendered":"\n

Class Members<\/h1>\n\n\n\n

Fields and methods inside classes are often referred to as “Class Members”:<\/p>\n\n\n\n

Create a Car<\/code> class with three class members: two fields<\/strong> and one method<\/strong>.<\/p>\n\n\n\n

\/\/ The class\nclass MyClass\n{\n  \/\/ Class members\n  string color = \"red\";        \/\/ field \u2588\u2588\u8fd9\u91cc\u5176\u5b9e\u5f88\u5173\u952e,\u8fd9\u91cc\u7684 color \u53eb Filed<\/mark><\/strong>\n  int maxSpeed = 200;          \/\/ field \u2588\u2588\u9ed8\u8ba4\u8bbf\u95ee\u6743\u9650\u662f private<\/mark><\/strong>\n  public void fullThrottle()   \/\/ method\n  {\n    Console.WriteLine(\"The car is going as fast as it can!\");\n  }\n}<\/code><\/pre>\n\n\n\n
Fields<\/h2>\n\n\n\n
\u2588\u2588 \u8fd9\u91cc\u5176\u5b9e\u5f88\u5173\u952e,\u6ce8\u610f\u53eb Filed \uff0c\u4f1a\u8ddf\u4ee5\u540e\u7684 Properties \u533a\u5206\uff01\uff01\uff01<\/mark><\/strong><\/p>\n\n\n\n
In the previous chapter, you learned that variables inside a class are called fields, and that you can access them by creating an object of the class, and by using the dot syntax (.<\/code>)<\/p>\n\n\n\n
class Car \n{\n  string color = \"red\";\/\/ \u2588\u2588\u9ed8\u8ba4\u662f private \u7684\uff0c\u53ea\u80fd\u5728\u7c7b\u91cc\u9762\u53ef\u89c1\uff01\uff01\uff01<\/mark><\/strong>\n  int maxSpeed = 200;\n\n  static void Main(string[] args)\n  {\n    Car myObj = new Car();\n    Console.WriteLine(myObj.color);\u3001\u3001\n    Console.WriteLine(myObj.maxSpeed);\n  }\n}<\/code><\/pre>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
Constructors<\/h1>\n\n\n\n
A constructor is a special method<\/strong> that is used to initialize objects. The advantage of a constructor, is that it is called when an object of a class is created<\/mark><\/strong>. It can be used to set initial values for fields.<\/p>\n\n\n\n
\u7c7b\u7684 \u6784\u9020\u51fd\u6570<\/strong> \u662f\u7c7b\u7684\u4e00\u4e2a\u7279\u6b8a\u7684\u6210\u5458\u51fd\u6570\uff0c\u5f53\u521b\u5efa\u7c7b\u7684\u65b0\u5bf9\u8c61\u65f6\u6267\u884c<\/mark><\/strong>\u3002
\u6784\u9020\u51fd\u6570\u7684\u540d\u79f0\u4e0e\u7c7b\u7684\u540d\u79f0\u5b8c\u5168\u76f8\u540c\uff0c\u5b83\u6ca1\u6709\u4efb\u4f55\u8fd4\u56de\u7c7b\u578b\u3002<\/p>\n\n\n\n
Note that the constructor name must match the class name<\/strong>, and it cannot have a return type<\/strong> (like void<\/code> or int<\/code>).<\/p>\n\n\n\n
Also note that the constructor is called when the object is created.<\/p>\n\n\n\n
All classes have constructors by default: if you do not create a class constructor yourself, C# creates one for you. However, then you are not able to set initial values for fields.<\/p>\n\n\n\n
Constructors save time!<\/strong> Take a look at the last example on this page to really understand why.<\/p>\n\n\n\n
\u9ed8\u8ba4\u7684\u6784\u9020\u51fd\u6570<\/strong>\u6ca1\u6709\u4efb\u4f55\u53c2\u6570\u3002<\/mark><\/p>\n\n\n\n
Access Modifiers \u8bbf\u95ee\u4fee\u9970\u7b26<\/h1>\n\n\n\n
By now, you are quite familiar with the public<\/code> keyword that appears in many of our examples:<\/p>\n\n\n\n
public string color;<\/code><\/pre>\n\n\n\n
The public<\/code> keyword is an access modifier<\/strong>, which is used to set the access level\/visibility for classes, fields, methods and properties<\/mark><\/strong>.<\/p>\n\n\n\n
C# has the following access modifiers:<\/p>\n\n\n\n
Modifier<\/th>Description<\/th><\/tr>
public<\/code><\/td>The code is accessible for all classes<\/td><\/tr>
private<\/code><\/td>The code is only accessible within the same class<\/td><\/tr>
protected<\/code><\/td>The code is accessible within the same class, or in a class that is inherited from that class. You will learn more about inheritance<\/a> in a later chapter<\/td><\/tr>
internal<\/code><\/td>The code is only accessible within its own assembly, but not from another assembly. You will learn more about this in a later chapter<\/td><\/tr><\/tbody><\/table>
C# \u4e2d\u8bbf\u95ee\u4fee\u9970\u7b26<\/figcaption><\/figure>\n\n\n\n
There’s also two combinations: protected internal<\/code> and private protected<\/code>.<\/p>\n\n\n\n
C# Properties (Get and Set)  \u2588\u2588 \u91cd\u70b9\uff01\uff01\uff01<\/h1>\n\n\n\n
Properties and Encapsulation<\/h2>\n\n\n\n
Before we start to explain properties, you should have a basic understanding of “Encapsulation<\/mark><\/strong>“. \uff08\u5c01\u88c5\uff09<\/mark><\/strong><\/p>\n\n\n\n
The meaning of Encapsulation<\/strong>, is to make sure that “sensitive” data is hidden from users. To achieve this, you must:<\/p>\n\n\n\n