Path.Combine Method (System.IO)

Combine Method

.NET Framework Class Library

Path..::.Combine Method

Combines two path strings.

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

Public Shared Function Combine ( _
    path1 As String, _
    path2 As String _
) As String

Visual Basic (Usage)

Dim path1 As String
Dim path2 As String
Dim returnValue As String

returnValue = Path.Combine(path1, _
    path2)

public static string Combine(
    string path1,
    string path2
)

Visual C++

public:
static String^ Combine(
    String^ path1, 
    String^ path2
)

JScript

public static function Combine(
    path1 : String, 
    path2 : String
) : String

Parameters

path1: Type: System..::.String
The first path.

path2: Type: System..::.String
The second path.

Return Value

Type: System..::.String
A string containing the combined paths. If one of the specified paths is a zero-length string, this method returns the other path. If path2 contains an absolute path, this method returns path2.

Exceptions

Exception	Condition
ArgumentException	path1 or path2 contain one or more of the invalid characters defined in GetInvalidPathChars.
ArgumentNullException	path1 or path2 is nullNothingnullptra null reference (Nothing in Visual Basic).

Remarks

If path1 is not a drive reference (that is, "C:" or "D:") and does not end with a valid separator character as defined in DirectorySeparatorChar, AltDirectorySeparatorChar, or VolumeSeparatorChar, DirectorySeparatorChar is appended to path1 before concatenation.

If path2 does not include a root (for example, if path2 does not start with a separator character or a drive specification), the result is a concatenation of the two paths, with an intervening separator character. If path2 includes a root, path2 is returned.

Because the parameters are not parsed if they have white space, if path2 is " c:\\ ", this will be appended to path1 instead of returning only path2.

Not all invalid characters for directory and file names are interpreted as unacceptable by the Combine method, because you can use these characters for search wildcard characters. For example, while Path.Combine("c:\\", "*.txt") might be invalid if you were to create a file from it, it is valid as a search string. It is therefore successfully interpreted by the Combine method.

For a list of common I/O tasks, see Common I/O Tasks.

Examples

The following code example demonstrates using the Combine method on a Windows-based desktop platform.

Visual Basic

Imports System
Imports System.IO

Public Class ChangeExtensionTest


    Public Shared Sub Main()
        Dim path1 As String = "c:\temp"
        Dim path2 As String = "subdir\file.txt"
        Dim path3 As String = "c:\temp.txt"
        Dim path4 As String = "c:^*&)(_=@#'\\^&#2.*(.txt"
        Dim path5 As String = ""
        Dim path6 As String = Nothing

        CombinePaths(path1, path2)
        CombinePaths(path1, path3)
        CombinePaths(path3, path2)
        CombinePaths(path4, path2)
        CombinePaths(path5, path2)
        CombinePaths(path6, path2)
    End Sub 'Main

    Private Shared Sub CombinePaths(p1 As String, p2 As String)

        Try
            Dim combination As String = Path.Combine(p1, p2)

            Console.WriteLine("When you combine '{0}' and '{1}', the result is: {2}'{3}'", p1, p2, Environment.NewLine, combination)
        Catch e As Exception
            Console.WriteLine("You cannot combine '{0}' and '{1}' because: {2}{3}", p1, p2, Environment.NewLine, e.Message)
        End Try

        Console.WriteLine()
    End Sub 'CombinePaths
End Class 'ChangeExtensionTest
' This code produces output similar to the following:
'
' When you combine 'c:\temp' and 'subdir\file.txt', the result is: 
' 'c:\temp\subdir\file.txt'
' 
' When you combine 'c:\temp' and 'c:\temp.txt', the result is: 
' 'c:\temp.txt'
' 
' When you combine 'c:\temp.txt' and 'subdir\file.txt', the result is: 
' 'c:\temp.txt\subdir\file.txt'
' 
' When you combine 'c:^*&)(_=@#'\^&#2.*(.txt' and 'subdir\file.txt', the result is: 
' 'c:^*&)(_=@#'\^&#2.*(.txt\subdir\file.txt'
' 
' When you combine '' and 'subdir\file.txt', the result is: 
' 'subdir\file.txt'
' 
' You cannot combine '' and 'subdir\file.txt' because: 
' Value cannot be null.
' Parameter name: path1

using System;
using System.IO;

public class ChangeExtensionTest {

    public static void Main() {

        string path1 = "c:\\temp";
        string path2 = "subdir\\file.txt";
        string path3 = "c:\\temp.txt";
        string path4 = "c:^*&)(_=@#'\\^&#2.*(.txt";
        string path5 = "";
        string path6 = null;

        CombinePaths(path1, path2);
        CombinePaths(path1, path3);
        CombinePaths(path3, path2);
        CombinePaths(path4, path2);
        CombinePaths(path5, path2);
        CombinePaths(path6, path2);
    }

    private static void CombinePaths(string p1, string p2) {

        try {
            string combination = Path.Combine(p1, p2);

            Console.WriteLine("When you combine '{0}' and '{1}', the result is: {2}'{3}'",
                        p1, p2, Environment.NewLine, combination);
        } catch (Exception e) {
            Console.WriteLine("You cannot combine '{0}' and '{1}' because: {2}{3}",
                        p1, p2, Environment.NewLine, e.Message);
        }

        Console.WriteLine();
    }
}
// This code produces output similar to the following:
//
// When you combine 'c:\temp' and 'subdir\file.txt', the result is: 
// 'c:\temp\subdir\file.txt'
// 
// When you combine 'c:\temp' and 'c:\temp.txt', the result is: 
// 'c:\temp.txt'
// 
// When you combine 'c:\temp.txt' and 'subdir\file.txt', the result is: 
// 'c:\temp.txt\subdir\file.txt'
// 
// When you combine 'c:^*&)(_=@#'\^&#2.*(.txt' and 'subdir\file.txt', the result is: 
// 'c:^*&)(_=@#'\^&#2.*(.txt\subdir\file.txt'
// 
// When you combine '' and 'subdir\file.txt', the result is: 
// 'subdir\file.txt'
// 
// You cannot combine '' and 'subdir\file.txt' because: 
// Value cannot be null.
// Parameter name: path1

Visual C++

using namespace System;
using namespace System::IO;
void CombinePaths( String^ p1, String^ p2 )
{
   try
   {
      String^ combination = Path::Combine( p1, p2 );
      Console::WriteLine( "When you combine '{0}' and '{1}', the result is: {2}'{3}'", p1, p2, Environment::NewLine, combination );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "You cannot combine '{0}' and '{1}' because: {2}{3}", p1, p2, Environment::NewLine, e->Message );
   }

   Console::WriteLine();
}

int main()
{
   String^ path1 = "c:\\temp";
   String^ path2 = "subdir\\file.txt";
   String^ path3 = "c:\\temp.txt";
   String^ path4 = "c:^*&)(_=@#'\\^&#2.*(.txt";
   String^ path5 = "";
   String^ path6 = nullptr;
   CombinePaths( path1, path2 );
   CombinePaths( path1, path3 );
   CombinePaths( path3, path2 );
   CombinePaths( path4, path2 );
   CombinePaths( path5, path2 );
   CombinePaths( path6, path2 );
}

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference

Path Class

Path Members

System.IO Namespace

Other Resources

File and Stream I/O

How to: Read Text from a File

How to: Write Text to a File