Directory.GetDirectoryRoot(String) 方法

定义

命名空间:
System.IO
程序集:
mscorlib.dll, System.IO.FileSystem.dll
程序集:
mscorlib.dll
程序集:
System.IO.FileSystem.dll
程序集:
netstandard.dll

返回指定路径的卷信息、根信息或两者。

public:
 static System::String ^ GetDirectoryRoot(System::String ^ path);
public static string GetDirectoryRoot(string path);
static member GetDirectoryRoot : string -> string
Public Shared Function GetDirectoryRoot (path As String) As String

参数

path
String

文件或目录的路径。

返回

String

一个字符串，包含指定路径的卷信息、根信息或两者。

例外

UnauthorizedAccessException

调用方没有所需的权限。

ArgumentException

低于 2.1 的 .NET Framework 和 .NET Core 版本： path 是长度为零的字符串，仅包含空格，或包含一个或多个无效字符。 可以使用 < a0/> 查询无效字符 。

ArgumentNullException

path 是 null。

PathTooLongException

指定的路径、文件名或两者都超过了系统定义的最大长度。

示例

下面的示例演示如何设置当前目录并显示目录根目录。

// This sample shows how to set the current directory and how to determine
// the root directory.
using System;
using System.IO;

namespace IOSamples
{
  public class DirectoryRoot
  {
    public static void Main()
    {
    // Create string for a directory. This value should be an existing directory
    // or the sample will throw a DirectoryNotFoundException.
      string dir = @"C:\test";		
      try
      {
          //Set the current directory.
          Directory.SetCurrentDirectory(dir);
      }
      catch (DirectoryNotFoundException e)
      {
          Console.WriteLine("The specified directory does not exist. {0}", e);
      }
    // Print to console the results.
      Console.WriteLine("Root directory: {0}", Directory.GetDirectoryRoot(dir));
      Console.WriteLine("Current directory: {0}", Directory.GetCurrentDirectory());
    }
  }
}
// The output of this sample depends on what value you assign to the variable dir.
// If the directory c:\test exists, the output for this sample is:
// Root directory: C:\
// Current directory: C:\test

// This sample shows how to set the current directory and how to determine
// the root directory.
open System.IO

// Create string for a directory. This value should be an existing directory
// or the sample will throw a DirectoryNotFoundException.
let dir = @"C:\test"
try
    //Set the current directory.
    Directory.SetCurrentDirectory dir
with :? DirectoryNotFoundException as e ->
    printfn $"The specified directory does not exist. {e}"
    
// Print to console the results.
printfn $"Root directory: {Directory.GetDirectoryRoot dir}"
printfn $"Current directory: {Directory.GetCurrentDirectory()}"
// The output of this sample depends on what value you assign to the variable dir.
// If the directory c:\test exists, the output for this sample is:
// Root directory: C:\
// Current directory: C:\test

' This sample shows how to set the current directory and how to determine
' the root directory.
Imports System.IO

Public Class DirectoryRoot
   
   Public Shared Sub Main()
      ' Create string for a directory. This value should be an existing directory
      ' or the sample will throw a DirectoryNotFoundException.
      Dim dir As String = "C:\test"
      Try
         'Set the current directory.
         Directory.SetCurrentDirectory(dir)
      Catch e As DirectoryNotFoundException
         Console.WriteLine("The specified directory does not exist. {0}", e)
      End Try
      ' Print to console the results.
      Console.WriteLine("Root directory: {0}", Directory.GetDirectoryRoot(dir))
      Console.WriteLine("Current directory: {0}", Directory.GetCurrentDirectory())
   End Sub
End Class
' The output of this sample depends on what value you assign to the variable dir.
' If the directory c:\test exists, the output for this sample is:
' Root directory: C:\
' Current directory: C:\test

注解

此方法获取由GetFullPath其返回的path完全限定路径名称，并返回根目录信息。 不存在指定的路径。

允许参数 path 指定相对路径或绝对路径信息。 相对路径信息解释为相对于当前工作目录。 若要获取当前工作目录，请参阅 GetCurrentDirectory。

参数的 path 区分大小写对应于运行代码的文件系统。 例如，它在 NTFS（默认 Windows 文件系统）上不区分大小写，在 Linux 文件系统上区分大小写。

有关常见 I/O 任务的列表，请参阅 常见 I/O 任务。

适用于

另请参阅