C＃|静态类

在C＃中，允许使用static关键字创建一个静态类。静态类只能包含静态数据成员，静态方法和静态构造函数，不允许创建静态类的对象。静态类是密封的，这意味着您不能从另一个类继承静态类。

句法：

static class Class_Name
{

      // static data members 
     // static method
}

在C＃中，静态类包含两种类型的静态成员，如下所示：

• 静态数据成员：由于静态类始终包含静态数据成员，因此使用static关键字声明静态数据成员，并使用类名直接访问它们。静态数据成员的内存是单独分配的，与对象没有任何关系。

  Synatx：

  static class Class_name 
  {
      public static nameofdatamember;
  }
  

• 静态方法：由于静态类始终包含静态方法，因此使用static关键字声明静态方法。这些方法仅访问静态数据成员，而不能访问非静态数据成员。

  Synatx：

  static class Class_name {
  
      public static nameofmethod()
      {
           // code 
       }
  }
  

范例1：

// C# program to illustrate the 
// concept of static class
using System;
  
namespace ExampleOfStaticClass {
  
// Creating static class
// Using static keyword
static class Author {
  
    // Static data members of Author
    public static string A_name = "Ankita";
    public static string L_name = "CSharp";
    public static int T_no = 84;
  
    // Static method of Author
    public static void details()
    {
        Console.WriteLine("The details of Author is:");
    }
}
  
// Driver Class
public class GFG {
  
    // Main Method
    static public void Main()
    {
  
        // Calling static method of Author
        Author.details();
  
        // Accessing the static data members of Author
        Console.WriteLine("Author name : {0} ", Author.A_name);
        Console.WriteLine("Language : {0} ", Author.L_name);
        Console.WriteLine("Total number of articles : {0} ", 
                                              Author.T_no);
    }
}
}

输出：

The details of Author is:
Author name : Ankita 
Language : CSharp 
Total number of articles : 84

范例2：

// C# program to demonstrate 
// the concept of static class
using System;
  
  
// declaring a static class
public static class GFG {
      
    // declaring static Method
    static void display()
    {
        Console.WriteLine("Static Method of class GFG");
    }
      
}
  
// trying to inherit the class GFG
// it will give error as static 
// class can't be inherited 
class GFG2 : GFG {
      
    public static void Main(String[] args) {
          
          
    }
}

编译时错误：

prog.cs(20,7): error CS0709: `GFG2′: Cannot derive from static class `GFG’

说明：在上面的示例中，我们使用static关键字将一个静态类命名为Author 。 Author类包含名为A_name ， L_name和T_no的静态数据成员，以及名为details()的静态方法。可以通过使用其类名如Author.details();来简单地调用静态类的方法。 。我们知道静态类不包含对象，因此可以通过其类名访问Author类的数据成员，例如Author.A_name ， Author.L_name和Author.T_no 。

静态和非静态类之间的区别

Static Class	Non-Static Class
Static class is defined using static keyword.	Non-Static class is not defined by using static keyword.
In static class, you are not allowed to create objects.	In non-static class, you are allowed to create objects using new keyword.
The data members of static class can be directly accessed by its class name.	The data members of non-static class is not directly accessed by its class name.
Static class always contains static members.	Non-static class may contain both static and non-static methods.
Static class does not contain an instance constructor.	Non-static class contains an instance constructor.
Static class cannot inherit from another class.	Non-static class can be inherited from another class.