c#总共有6个访问修饰符:

private:使用此可访问性声明的成员可以在包含类型中可见，但对任何派生类型、同一程序集中的其他类型或包含程序集中之外的类型都不可见。也就是说，访问仅限于包含类型。

protected:使用此可访问性声明的成员可以在包含程序集中从包含类型派生的类型中可见，也可以在包含程序集中从包含类型派生的类型中可见。也就是说，只能访问包含类型的派生类型。

internal:使用此可访问性声明的成员可以在包含该成员的程序集内可见，它对包含该成员的程序集之外的任何程序集都不可见。也就是说，访问仅限于包含程序集。

internal protected:使用此可访问性声明的成员可以在包含程序集内部或外部从包含类型派生的类型中可见，它也对包含程序集内的任何类型可见。也就是说，访问仅限于包含程序集或派生类型。

public:使用此可访问性声明的成员可以在包含此成员的程序集或引用包含该成员的程序集的任何其他程序集中可见。也就是说，访问不受限制。

在c# 7.2中，增加了一个新的可访问性级别:

private protected:使用此可访问性声明的成员可以在包含程序集中从此包含类型派生的类型中可见。对于非从包含类型派生的任何类型或包含程序集外部的任何类型都不可见。也就是说，访问权限仅限于包含程序集中的派生类型。

源代码，包括新的私有受保护访问修饰符的示例代码

Private状态表示变量只能被同一类的对象访问。受保护状态将这种访问权限扩展到该类的后代。

“从上表中我们可以看到隐私和受保护之间的区别……我认为两者是一样的....那么这两个单独的命令有什么用呢?

查看MSDN链接了解更多信息

公共-任何人在任何地方都可以访问。 Private -只能从它所属的类中的with访问。 Protected -只能从类中的with或从类继承的任何对象访问。

除了在VB中，没有什么是像null的。 静态意味着你有那个对象的一个实例，那个类的每个实例都有方法。

public means that it can be accessed by any class in any assembly, which includes the class itself. protected internal means it can be accessed by the class itself (in the class definition), and it can be accessed by any class in the current assembly, but outside of the assembly it can only be accessed by a class that inherits the class, or by the class itself (if it is a partial class) – basically it means internal inside the assembly and protected outside of the assembly. protected means it can only be accessed by the class itself, or accessed by a class that inherits it and that class can be in any assembly internal means it can be accessed by the class itself or by any class in the assembly but can't be accessed at all outside of the assembly unless by the class itself (i.e. it is a partial class) private protected means it can only be accessed by the class itself, or it can be accessed by a class that inherits it and only if that class is in the current assembly. Outside of the assembly, it can only be accessed by the class itself (i.e. it is a partial class) – basically combines internal and protected, or another way of putting it is it's private outside of the assembly and protected inside the assembly. private means that it can only be accessed by the class itself no access modifier: The default access for everything in C# is "the most restricted access you could declare for that member"., which is private for a member / method / nested class in a class and internal for a non-nested class.

In the above text 'accessed' means accessed via an object of the class type, which within a method of the class itself will be the implicit this object, or perhaps the method instantiates an explicit object of the current class type and accesses it through that object. Both are considered to be being accessed by the class itself and therefore the access rules are the same. This also applies to an access being performed from a static method, or when it is a static member / method being accessed, except the access is performed using the class scope and not and object. A member / method of a static class needs to be explicitly made static or it won't compile.

没有嵌套的类可以是公共的，也可以是内部的，默认情况下是内部的。嵌套的类可以是任何访问类型，如果父类是静态的，它就不需要是静态的，它的成员也不需要是静态的。内部类意味着只能实例化它或从当前程序集访问它的静态成员。

您可以在内部或私有嵌套类中拥有公共成员/方法/嵌套类——只有访问说明符(在正在进行的访问的完全限定名称中)低于当前正在进行的访问所需的级别才能阻止访问。

Inheritance in C# is always public unlike C++, which can privately or protectedly inherit, which then changes the access of all classes that then inherit from the class that is inheriting from this class, as well as the access via object / via class scope of type of the class that inheriting privately / protectedly from the class and the class that is inheriting from the class that is inheriting privately / protectedly form the class, and so on. The access is changed such that all access modifiers less restrictive than private or protected are made private and protected respectively.

c#中所有访问修饰符的描述

c#总共有6个访问修饰符:

private:使用此可访问性声明的成员可以在包含类型中可见，但对任何派生类型、同一程序集中的其他类型或包含程序集中之外的类型都不可见。也就是说，访问仅限于包含类型。

protected:使用此可访问性声明的成员可以在包含程序集中从包含类型派生的类型中可见，也可以在包含程序集中从包含类型派生的类型中可见。也就是说，只能访问包含类型的派生类型。

internal:使用此可访问性声明的成员可以在包含该成员的程序集内可见，它对包含该成员的程序集之外的任何程序集都不可见。也就是说，访问仅限于包含程序集。

internal protected:使用此可访问性声明的成员可以在包含程序集内部或外部从包含类型派生的类型中可见，它也对包含程序集内的任何类型可见。也就是说，访问仅限于包含程序集或派生类型。

public:使用此可访问性声明的成员可以在包含此成员的程序集或引用包含该成员的程序集的任何其他程序集中可见。也就是说，访问不受限制。

在c# 7.2中，增加了一个新的可访问性级别:

private protected:使用此可访问性声明的成员可以在包含程序集中从此包含类型派生的类型中可见。对于非从包含类型派生的任何类型或包含程序集外部的任何类型都不可见。也就是说，访问权限仅限于包含程序集中的派生类型。

源代码，包括新的私有受保护访问修饰符的示例代码