Path.IsPathFullyQualified Method

Definition

Overloads

Remarks

The overloads of the IsPathFullyQualified method handle paths that use both the DirectorySeparatorChar and the AltDirectorySeparatorChar characters. It does not perform any validation on the path that is passed to it as an argument. As a result, URIs are interpreted as relative paths and return false.

There is a difference between a fully qualified path (as indicated by the IsPathFullyQualified method) and a rooted path (as indicated by the IsPathRooted method). A fully qualified path or absolute path always defines an exact path from a particular drive or device to a target file or directory, and does not depend on the current drive or current directory. For example, on Windows systems, C:/users/user1/documents/reports/2019/january/highlights.pdf defines an absolute path from the root of the C: drive to the target file, highlights.pdf. A rooted path specifies either a starting drive or root directory, but depends on either the current directory (if it is rooted by a specified drive) or the current drive (if it is rooted by the root directory). The following example illustrates the difference between fully qualified paths and rooted paths.

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

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

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

static member IsPathFullyQualified : ReadOnlySpan<char> -> bool

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

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

public static bool IsPathFullyQualified(string path);

static member IsPathFullyQualified : string -> bool

Public Shared Function IsPathFullyQualified (path As String) As Boolean