Directory.Exists(String) Metoda

Definicja

Określa, czy dana ścieżka odwołuje się do istniejącego katalogu na dysku.Determines whether the given path refers to an existing directory on disk.

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

Parametry

path
String

Ścieżka do przetestowania.The path to test.

Zwraca

true, jeśli path odwołuje się do istniejącego katalogu; false, jeśli katalog nie istnieje lub wystąpi błąd podczas próby ustalenia, czy określony katalog istnieje.true if path refers to an existing directory; false if the directory does not exist or an error occurs when trying to determine if the specified directory exists.

Przykłady

Poniższy przykład pobiera tablicę nazw plików lub katalogów w wierszu polecenia, określa rodzaj nazwy, a także przetwarza odpowiednie.The following example takes an array of file or directory names on the command line, determines what kind of name it is, and processes it appropriately.

// For File::Exists, Directory::Exists
using namespace System;
using namespace System::IO;
using namespace System::Collections;

// Insert logic for processing found files here.
void ProcessFile( String^ path )
{
   Console::WriteLine( "Processed file '{0}'.", path );
}


// Process all files in the directory passed in, recurse on any directories 
// that are found, and process the files they contain.
void ProcessDirectory( String^ targetDirectory )
{
   
   // Process the list of files found in the directory.
   array<String^>^fileEntries = Directory::GetFiles( targetDirectory );
   IEnumerator^ files = fileEntries->GetEnumerator();
   while ( files->MoveNext() )
   {
      String^ fileName = safe_cast<String^>(files->Current);
      ProcessFile( fileName );
   }

   
   // Recurse into subdirectories of this directory.
   array<String^>^subdirectoryEntries = Directory::GetDirectories( targetDirectory );
   IEnumerator^ dirs = subdirectoryEntries->GetEnumerator();
   while ( dirs->MoveNext() )
   {
      String^ subdirectory = safe_cast<String^>(dirs->Current);
      ProcessDirectory( subdirectory );
   }
}

int main( int argc, char *argv[] )
{
   for ( int i = 1; i < argc; i++ )
   {
      String^ path = gcnew String(argv[ i ]);
      if ( File::Exists( path ) )
      {
         
         // This path is a file
         ProcessFile( path );
      }
      else
      if ( Directory::Exists( path ) )
      {
         
         // This path is a directory
         ProcessDirectory( path );
      }
      else
      {
         Console::WriteLine( "{0} is not a valid file or directory.", path );
      }

   }
}

// For File.Exists, Directory.Exists
using System;
using System.IO;
using System.Collections;

public class RecursiveFileProcessor 
{
    public static void Main(string[] args) 
    {
        foreach(string path in args) 
        {
            if(File.Exists(path)) 
            {
                // This path is a file
                ProcessFile(path); 
            }               
            else if(Directory.Exists(path)) 
            {
                // This path is a directory
                ProcessDirectory(path);
            }
            else 
            {
                Console.WriteLine("{0} is not a valid file or directory.", path);
            }        
        }        
    }

    // Process all files in the directory passed in, recurse on any directories 
    // that are found, and process the files they contain.
    public static void ProcessDirectory(string targetDirectory) 
    {
        // Process the list of files found in the directory.
        string [] fileEntries = Directory.GetFiles(targetDirectory);
        foreach(string fileName in fileEntries)
            ProcessFile(fileName);

        // Recurse into subdirectories of this directory.
        string [] subdirectoryEntries = Directory.GetDirectories(targetDirectory);
        foreach(string subdirectory in subdirectoryEntries)
            ProcessDirectory(subdirectory);
    }
        
    // Insert logic for processing found files here.
    public static void ProcessFile(string path) 
    {
        Console.WriteLine("Processed file '{0}'.", path);	    
    }
}
' For File.Exists, Directory.Exists 

Imports System.IO
Imports System.Collections

Public Class RecursiveFileProcessor

    Public Overloads Shared Sub Main(ByVal args() As String)
        Dim path As String
        For Each path In args
            If File.Exists(path) Then
                ' This path is a file.
                ProcessFile(path)
            Else
                If Directory.Exists(path) Then
                    ' This path is a directory.
                    ProcessDirectory(path)
                Else
                    Console.WriteLine("{0} is not a valid file or directory.", path)
                End If
            End If
        Next path
    End Sub


    ' Process all files in the directory passed in, recurse on any directories 
    ' that are found, and process the files they contain.
    Public Shared Sub ProcessDirectory(ByVal targetDirectory As String)
        Dim fileEntries As String() = Directory.GetFiles(targetDirectory)
        ' Process the list of files found in the directory.
        Dim fileName As String
        For Each fileName In fileEntries
            ProcessFile(fileName)

        Next fileName
        Dim subdirectoryEntries As String() = Directory.GetDirectories(targetDirectory)
        ' Recurse into subdirectories of this directory.
        Dim subdirectory As String
        For Each subdirectory In subdirectoryEntries
            ProcessDirectory(subdirectory)
        Next subdirectory

    End Sub

    ' Insert logic for processing found files here.
    Public Shared Sub ProcessFile(ByVal path As String)
        Console.WriteLine("Processed file '{0}'.", path)
    End Sub
End Class

Uwagi

Parametr path może określać informacje o ścieżce względnej lub bezwzględnej.The path parameter is permitted to specify relative or absolute path information. Informacje o ścieżce względnej są interpretowane jako względne w stosunku do bieżącego katalogu roboczego.Relative path information is interpreted as relative to the current working directory.

Spacje końcowe są usuwane z końca parametru path przed sprawdzeniem, czy katalog istnieje.Trailing spaces are removed from the end of the path parameter before checking whether the directory exists.

W parametrze path nie jest rozróżniana wielkość liter.The path parameter is not case-sensitive.

Jeśli nie masz co najmniej uprawnienia tylko do odczytu do katalogu, Metoda Exists zwróci false.If you do not have at a minimum read-only permission to the directory, the Exists method will return false.

Metoda Exists zwraca false, jeśli wystąpi błąd podczas próby ustalenia, czy określony plik istnieje.The Exists method returns false if any error occurs while trying to determine if the specified file exists. Może się to zdarzyć w sytuacjach, w których są wywoływane wyjątki, takie jak przekazywanie nazwy pliku z nieprawidłowymi znakami lub zbyt wiele znaków, Niepowodzenie lub brak dysku lub jeśli obiekt wywołujący nie ma uprawnienia do odczytu pliku.This can occur in situations that raise exceptions such as passing a file name with invalid characters or too many characters, a failing or missing disk, or if the caller does not have permission to read the file.

Zabezpieczenia

FileIOPermission
do odczytywania plików.for reading files. Skojarzone Wyliczenie: ReadAssociated enumeration: Read

Dotyczy

Zobacz też