错误的Directory.GetParent？ [英] Bug in Directory.GetParent?

问题描述

我是一个非常怪异的行为的 System.IO.Directory.GetParent 法打在脸上：

 字符串路径1 = @C：\富\酒吧;
DirectoryInfo的parent1 = Directory.GetParent（路径1）;
Console.WriteLine（parent1.FullName）; //打印C：\ FOO，符合市场预期

//注意额外的反斜杠。它应该仍然指向同一个位置，对不对？
字符串PATH2 = @C：\富\酒吧\;
DirectoryInfo的parent2 = Directory.GetParent（路径2）;
Console.WriteLine（parent2.FullName）; //打印C：\富\吧！
 

我会认为这是一个错误，但由于1.0这种方法已经在那里，所以我想它会被现在的检测。在另一方面，如果它的设计，我想不出一个合理的解释，这样的设计...

你怎么看？是不是一个错误？如果没有，你怎么解释这种现象？

解决方案

一些谷歌搜索显示的一些想法：

  DirectoryInfo的迪=新的DirectoryInfo（@C：\父\子）;
Console.WriteLine（di.Parent.FullName）;
 

和

  DirectoryInfo的迪=新的DirectoryInfo（@C：\父\子\）;
Console.WriteLine（di.Parent.FullName）;
 

     

都返回C：\父

     

我只能假设 Directory.GetParent（...）不能假定 C：\父\子是一个目录，而不是有没有文件扩展名的文件。 的DirectoryInfo 就可以了，因为你构造对象的方式。

---

个人我认为是，当有一个反斜杠，该字符串被视为一个路径零文件的目录中（也就是，没有名和扩展名的文件）。显然，那些可以存在（应该有一个链接，但由于某些原因，我无法找到任何东西）。

尝试构建一个的FileInfo 对象从路径2 的。你会看到它的正确构建，已的String.Empty 正如其名和扩展名，不存在并具有 C：\富\酒吧为目录名。鉴于此，这种情况是有道理的：对于这种零文件的父对象确实是 C：\富\酒吧

I was hit in the face by a very weird behavior of the System.IO.Directory.GetParent method:

string path1 = @"C:\foo\bar";
DirectoryInfo parent1 = Directory.GetParent(path1);
Console.WriteLine (parent1.FullName); // Prints C:\foo, as expected

// Notice the extra backslash. It should still refer to the same location, right ?
string path2 = @"C:\foo\bar\";
DirectoryInfo parent2 = Directory.GetParent(path2);
Console.WriteLine (parent2.FullName); // Prints C:\foo\bar !!!

I would consider it a bug, but this method has been there since 1.0, so I guess it would have been detected by now. On the other hand, if it's as designed, I can't think of a sensible explanation for such a design...

What do you think ? Is it a bug ? If not, how do you explain this behavior ?

解决方案

Some googling reveals some thoughts:

DirectoryInfo di = new DirectoryInfo(@"C:\parent\child");
Console.WriteLine(di.Parent.FullName);

and

DirectoryInfo di = new DirectoryInfo(@"C:\parent\child\");
Console.WriteLine(di.Parent.FullName);

Both return "C:\parent"

I can only assume Directory.GetParent(...) can't assume that C:\parent\child is a directory instead of a file with no file extension. DirectoryInfo can, because you're constructing the object that way.

---

Personally what I think is that when there is a backslash, the string is treated as a path to the "null file" inside the directory (that is, a file with no name and extension). Apparently, those can exist (there should be a link, but for some reason I can't find anything).

Try constructing a FileInfo object out of path2. You'll see it's properly constructed, has String.Empty as its name and extension, does not exist and has C:\foo\bar as its DirectoryName. Given that, the situation makes sense: the parent object for this "null file" is indeed C:\foo\bar.

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