Why Can't I Inherit IO.Directory?

问题

Why can't I create a class in VB.NET that inherits System.IO.Directory? According to Lutz Roeder, it is not declared as NotInheritable!

I want to create a utility class that adds functionality to the Directory class. For instance, I want to add a Directory.Move function.

Please advise and I will send you a six pack. OK nevermind I'm not sending you anything but if you come to the bar tonight I will hook you up and then beat you in pool.

回答1:

From the Meta Data of .NET

namespace System.IO
{
    // Summary:
    //     Exposes static methods for creating, moving, and enumerating through directories
    //     and subdirectories. This class cannot be inherited.
    [ComVisible(true)]
    public static class Directory

You cannot inherit from a Static Class.

回答2:

Are you using C# 3.0 VB.NET 2008 -- then you could add an Extension Method

回答3:

If you use the DirectoryInfo class, you will have access to a MoveTo function.

EDIT: I'll correct myself... The static Directory class already has a Move method.

回答4:

I'd guess that Reflector isn't picking up the sealed attribute correctly for VB (or perhaps just not displaying it properly). If you look at the IL, it is sealed:

class public abstract auto ansi sealed beforefieldinit Directory

来源：https://stackoverflow.com/questions/135759/why-cant-i-inherit-io-directory