Question

在C＃System.IO.DriveInfo中有属性DriveType。

System.IO.DriveType是一个枚举：

public enum DriveType
{
    Unknown = 0,
    //
    // Summary:
    //     The drive does not have a root directory.
    NoRootDirectory = 1,
    Removable = 2,
    Fixed = 3,
    Network = 4,
    CDRom = 5,
    Ram = 6,
}

我怀疑这是一个没有驱动器号的卷。但是使用：

System.IO.DriveInfo.GetDrives();

如果没有驱动器号，

不会列出我的音量。

NoRootDirectory是否用于任何其他类型的卷/驱动器，或System.IO.DriveInfo.GetDrives()只是不显示它们？

Answer 1

System.IO.DriveType.NoRootDirectory似乎是误导性地指定＆＃34; 此驱动器号未使用＆＃34;

所有驱动器的测试代码：所有未找到的驱动器都具有类型 DriveType.NoRootDirectory

foreach (char driveLetter in "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToArray())
{
    var driveInfo = new System.IO.DriveInfo(driveLetter.ToString() + ":\\");

    if(System.IO.DriveInfo.GetDrives().FirstOrDefault(o => o.Name[0] == driveLetter) == null)
        Console.WriteLine("// Not found: " + driveInfo.Name + " has DriveType: " + driveInfo.DriveType.ToString());
    else
        Console.WriteLine("//     found: " + driveInfo.Name + " has DriveType: " + driveInfo.DriveType.ToString());
}

结果：

// Not found: A:\ has DriveType: NoRootDirectory
// Not found: B:\ has DriveType: NoRootDirectory
//     found  C:\ has DriveType: Fixed
//     found  D:\ has DriveType: CDRom
// Not found: E:\ has DriveType: NoRootDirectory
// Not found: F:\ has DriveType: NoRootDirectory
// Not found: G:\ has DriveType: NoRootDirectory
// Not found: H:\ has DriveType: NoRootDirectory
// Not found: I:\ has DriveType: NoRootDirectory
// Not found: J:\ has DriveType: NoRootDirectory
// Not found: K:\ has DriveType: NoRootDirectory
// Not found: L:\ has DriveType: NoRootDirectory
// Not found: M:\ has DriveType: NoRootDirectory
// Not found: N:\ has DriveType: NoRootDirectory
// Not found: O:\ has DriveType: NoRootDirectory
//     found  P:\ has DriveType: Network
// Not found: Q:\ has DriveType: NoRootDirectory
//     found  R:\ has DriveType: Network
//     found  S:\ has DriveType: Network
// Not found: T:\ has DriveType: NoRootDirectory
// Not found: U:\ has DriveType: NoRootDirectory
//     found  V:\ has DriveType: Network
//     found  W:\ has DriveType: Fixed
//     found  X:\ has DriveType: Network
//     found  Y:\ has DriveType: Network
//     found  Z:\ has DriveType: Network

以前的例子（在编辑这篇文章之前）：

但是：这只是一个使用NoRootDirectory的案例。它没有回答是否存在其他星座的问题。

这里是测试代码：

// J:\ is an unused drive letter var xDummy1 = new System.IO.DriveInfo("J:\\"); Console.WriteLine(xDummy1.Name); // result: J:\ Console.WriteLine(xDummy1.DriveType); // result: NoRootDirectory Console.WriteLine(xDummy1.IsReady); // result: False // Console.WriteLine(xDummy1.DriveFormat); // would throw an DriveNotFoundException Console.WriteLine(System.IO.Directory.Exists("j:\\")); // result: False // S:\ is an mapped drive to a currently not available share var xDummy2 = new System.IO.DriveInfo("S:\\"); Console.WriteLine(xDummy2.Name); // result: S:\ Console.WriteLine(xDummy2.DriveType); // result: Network Console.WriteLine(xDummy2.IsReady); // result: False // Console.WriteLine(xDummy2.DriveFormat); // would throw an IOException Console.WriteLine(System.IO.Directory.Exists("S:\\")); // result: False

~~我已经测试了一些使用但不存在的驱动器的更多组合，但没有一个返回NoRootDirectory。~~

Answer 2

我知道它用于未分配的驱动器号。当然，您不会让他们通过GetDrives，而是尝试new System.IO.DriveInfo("B:").DriveType之类的方法。它也可以用于未格式化的分区（或未知的文件系统），但是我不确定（在这种情况下，您必须测试是否得到Unknown或NoRootDirectory）。为了完整起见，您还可以通过转到HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices并创建指向X:的驱动器\Device\Null来创建垃圾驱动器，然后查看获得的结果。

实际上，documentation for the underlying WinAPI function GetDriveType更加清晰。它说：

根路径无效；例如，在指定的路径上没有安装卷。

我将“根路径无效”解释为“内核路径\DosDevices\X:无法解析/链接到能够解析对路径\的请求的有效文件系统目录对象”。

该句子可能是由具有Windows内核知识的人写的。在这种情况下，我假设上面的“垃圾驱动器”也会为您提供该值以及所有未分配的驱动器号。

要详细了解我刚才提到的内容，如果有兴趣，请查看http://www.osronline.com/article.cfm%5eid=107.htm。

Answer 3

//Check fixed local drive
string path= "C\MyFolder\myfile.txt";
string root = Path.GetPathRoot(path);

if (DriveInfo.GetDrives().FirstOrDefault(d => d.Name == root).DriveType == DriveType.Fixed)
{
    MessageBox.Show(root);
}

什么样的驱动器是“NoRootDirectory”（System.IO.DriveType.NoRootDirectory）？

3 个答案: