Path.IsPathRooted 方法

定义

命名空间:

System.IO

程序集:

System.Runtime.dll

返回一个值，指示文件路径是否包含根。

重载

IsPathRooted(ReadOnlySpan<Char>)	返回一个值，该值指示表示文件路径的指定字符范围是否包含根。
IsPathRooted(String)	返回一个值，该值指示指定的路径字符串是否包含根。

注解

根路径是固定到特定驱动器或 UNC 路径的文件路径;它与相对于当前驱动器或工作目录的路径形成对比。 例如，在 Windows 系统上，根路径以反斜杠开头， (例如“\Documents”) 或驱动器号和冒号 (例如“C：Documents”) 。

请注意，根路径可以是绝对 (即完全限定) 或相对路径。 绝对根路径是从驱动器根目录到特定目录的完全限定路径。 相对根路径指定驱动器，但其完全限定路径针对当前目录解析。 以下示例演示了差异。

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string relative1 = "C:Documents"; 
        ShowPathInfo(relative1);

        string relative2 = "/Documents";
        ShowPathInfo(relative2);

        string absolute = "C:/Documents";
        ShowPathInfo(absolute);
    }

    private static void ShowPathInfo(string path)
    {
        Console.WriteLine($"Path: {path}");
        Console.WriteLine($"   Rooted: {Path.IsPathRooted(path)}");
        Console.WriteLine($"   Fully qualified: {Path.IsPathFullyQualified(path)}");
        Console.WriteLine($"   Full path: {Path.GetFullPath(path)}");
        Console.WriteLine();
    }
}
// The example displays the following output when run on a Windows system:
//    Path: C:Documents
//        Rooted: True
//        Fully qualified: False
//        Full path: c:\Users\user1\Documents\projects\path\ispathrooted\Documents
//
//    Path: /Documents
//       Rooted: True
//       Fully qualified: False
//       Full path: c:\Documents
//
//    Path: C:/Documents
//       Rooted: True
//       Fully qualified: True
//       Full path: C:\Documents

Imports System.IO

Module Program
    Public Sub Main()
        Dim relative1 As String = "C:Documents" 
        ShowPathInfo(relative1)

        Dim relative2 As String = "C:Documents" 
        ShowPathInfo(relative2)

        Dim absolute As String = "C:/Documents"
        ShowPathInfo(absolute)
    End Sub

    Private Sub ShowPathInfo(filepath As String)
        Console.WriteLine($"Path: {filepath}")
        Console.WriteLine($"   Rooted: {Path.IsPathRooted(filepath)}")
        Console.WriteLine($"   Fully qualified: {Path.IsPathFullyQualified(filepath)}")
        Console.WriteLine($"   Full path: {Path.GetFullPath(filepath)}")
        Console.WriteLine()
    End Sub
End Module
' The example displays the following output when run on a Windows system:
'    Path: C:Documents
'        Rooted: True
'        Fully qualified: False
'        Full path: c:\Users\user1\Documents\projects\path\ispathrooted\Documents
'
'    Path: /Documents
'       Rooted: True
'       Fully qualified: False
'       Full path: c:\Documents
'
'    Path: C:/Documents
'       Rooted: True
'       Fully qualified: True
'       Full path: C:\Documents

IsPathRooted(ReadOnlySpan<Char>)

Source:

Path.Unix.cs

返回一个值，该值指示表示文件路径的指定字符范围是否包含根。

public:
 static bool IsPathRooted(ReadOnlySpan<char> path);

public static bool IsPathRooted (ReadOnlySpan<char> path);

static member IsPathRooted : ReadOnlySpan<char> -> bool

Public Shared Function IsPathRooted (path As ReadOnlySpan(Of Char)) As Boolean

参数

path

ReadOnlySpan<Char>

要测试的路径。

返回

Boolean

如果 path 包含一个根，则为 true；否则为 false。

另请参阅

• Windows 系统中的文件路径格式

IsPathRooted(String)

Source:

Path.Unix.cs

返回一个值，该值指示指定的路径字符串是否包含根。

public:
 static bool IsPathRooted(System::String ^ path);

public static bool IsPathRooted (string? path);

static member IsPathRooted : string -> bool

Public Shared Function IsPathRooted (path As String) As Boolean

参数

path

String

要测试的路径。

返回

Boolean

如果 path 包含一个根，则为 true；否则为 false。

例外

ArgumentException

.NET Framework 和 2.1 之前的 .NET Core 版本：path包含 中GetInvalidPathChars()定义的一个或多个无效字符。

示例

以下示例演示如何 IsPathRooted 使用 方法测试三个字符串。

String^ fileName = "C:\\mydir\\myfile.ext";
String^ UncPath = "\\\\myPc\\mydir\\myfile";
String^ relativePath = "mydir\\sudir\\";
bool result;
result = Path::IsPathRooted( fileName );
Console::WriteLine( "IsPathRooted('{0}') returns {1}", fileName, result.ToString() );
result = Path::IsPathRooted( UncPath );
Console::WriteLine( "IsPathRooted('{0}') returns {1}", UncPath, result.ToString() );
result = Path::IsPathRooted( relativePath );
Console::WriteLine( "IsPathRooted('{0}') returns {1}", relativePath, result.ToString() );

// This code produces output similar to the following:
//
// IsPathRooted('C:\mydir\myfile.ext') returns True
// IsPathRooted('\\myPc\mydir\myfile') returns True
// IsPathRooted('mydir\sudir\') returns False

string fileName = @"C:\mydir\myfile.ext";
string UncPath = @"\\myPc\mydir\myfile";
string relativePath = @"mydir\sudir\";
bool result;

result = Path.IsPathRooted(fileName);
Console.WriteLine("IsPathRooted('{0}') returns {1}",
    fileName, result);

result = Path.IsPathRooted(UncPath);
Console.WriteLine("IsPathRooted('{0}') returns {1}",
    UncPath, result);

result = Path.IsPathRooted(relativePath);
Console.WriteLine("IsPathRooted('{0}') returns {1}",
    relativePath, result);

// This code produces output similar to the following:
//
// IsPathRooted('C:\mydir\myfile.ext') returns True
// IsPathRooted('\\myPc\mydir\myfile') returns True
// IsPathRooted('mydir\sudir\') returns False

Dim fileName As String = "C:\mydir\myfile.ext"
Dim UncPath As String = "\\myPc\mydir\myfile"
Dim relativePath As String = "mydir\sudir\"
Dim result As Boolean

result = Path.IsPathRooted(fileName)
Console.WriteLine("IsPathRooted('{0}') returns {1}", fileName, result)

result = Path.IsPathRooted(UncPath)
Console.WriteLine("IsPathRooted('{0}') returns {1}", UncPath, result)

result = Path.IsPathRooted(relativePath)
Console.WriteLine("IsPathRooted('{0}') returns {1}", relativePath, result)

' This code produces output similar to the following:
'
' IsPathRooted('C:\mydir\myfile.ext') returns True
' IsPathRooted('\\myPc\mydir\myfile') returns True
' IsPathRooted('mydir\sudir\') returns False

注解

IsPathRooted如果第一个字符是目录分隔符（如“\”），或者路径以驱动器号和冒号开头 (：) ，则方法返回 true 。 例如，它为path字符串（如“\\MyDir\MyFile.txt”、“C：\MyDir”或“C：MyDir”）返回 true 。 它为path字符串（如“MyDir”）返回 false 。

此方法不验证路径或文件名是否存在。

有关常见 I/O 任务的列表，请参阅 常见 I/O 任务。

另请参阅

• Windows 系统中的文件路径格式
• 文件和流 I/O
• 如何：从文件中读取文本
• 如何：将文本写入文件