C#中受保护的方法继承

Question

我在阅读有关受保护访问修饰符的文档后编写了一个简单的 C# 代码，但我收到了很多不合逻辑的错误。我找不到任何解决方案。

using System;

public class WeaponController
{
    protected void Reload()
    {
        Console.WriteLine("Reload");
    }

    protected virtual void Shoot()
    {

    }
}

public class SMGController : WeaponController
{

    private override void Shoot()
    {
        Console.WriteLine("Shoot");
    }
}

public class Test
{
    public static void Main()
    {
        var test = new SMGController();
        test.Shoot();
        test.Reload();
    }
}

我收到以下错误：

prog.cs(19,27): error CS0621: SMGController.Shoot()': virtual or abstract members cannot be private prog.cs(19,27): error CS0507:SMGController.Shoot()': cannot change access modifiers when overriding protected' inherited memberWeaponController.Shoot()' prog.cs(10,25): (Location of the symbol related to previous error) Compilation failed: 2 error(s), 0 warnings

如果我将 SMGController 中 Shoot() 方法的访问修饰符更改为受保护，我会收到更多错误：

prog.cs(30,8): error CS1540: Cannot access protected member WeaponController.Shoot()' via a qualifier of typeSMGController'. The qualifier must be of type Test' or derived from it prog.cs(10,25): (Location of the symbol related to previous error) prog.cs(30,8): error CS0122:WeaponController.Shoot()' is inaccessible due to its protection level prog.cs(10,25): (Location of the symbol related to previous error) prog.cs(31,8): error CS1540: Cannot access protected member WeaponController.Reload()' via a qualifier of typeSMGController'. The qualifier must be of type Test' or derived from it prog.cs(5,17): (Location of the symbol related to previous error) prog.cs(31,8): error CS0122:WeaponController.Reload()' is inaccessible due to its protection level prog.cs(5,17): (Location of the symbol related to previous error) Compilation failed: 4 error(s), 0 warnings

我的代码有什么问题？

Answer 1

您不能从 class 外部调用 protected 方法，即从 Test.

调用 WeaponController.Shoot

此外，如果您覆盖 protected 方法，它也必须是 protected。

显然，您希望 Reload 和 Shoot 为 public，因此您可以从 Test.Main.

调用它们

Answer 2

protected修饰符意味着只有class本身或子class可以访问Shoot。

您正试图从与 SMGController 和 WeaponController 都没有继承关系的其他 class Test 访问它，并且这种访问被protected修饰符。

供参考，参见https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/protected，尤其是第一节中的这一行：

A protected member is accessible within its class and by derived class instances.

您可以通过 Shoot public 来解决这个问题。或者，如果您坚持保留它 protected，那么您需要添加一个方法，例如public PublicShoot() 然后调用受保护的方法。

C#中受保护的方法继承

Protected method inheritance in C#

c#

oop

inheritance

protected