Directory.Exists(String) Metodo
Definizione
Importante
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Determina se il percorso specificato fa riferimento a una directory esistente sul disco.
public:
static bool Exists(System::String ^ path);
public static bool Exists (string path);
public static bool Exists (string? path);
static member Exists : string -> bool
Public Shared Function Exists (path As String) As Boolean
Parametri
- path
- String
Percorso da testare.
Restituisce
true
se path
fa riferimento a una directory esistente; false
se la directory non esiste o si verifica un errore durante il tentativo di determinare se la directory specificata esiste.
Esempio
L'esempio seguente accetta una matrice di nomi di file o directory nella riga di comando, determina il tipo di nome e lo elabora in modo appropriato.
// 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);
}
}
module RecursiveFileProcessor
open System.IO
// Insert logic for processing found files here.
let processFile path =
printfn $"Processed file '%s{path}'."
// Process all files in the directory passed in, recurse on any directories
// that are found, and process the files they contain.
let rec processDirectory targetDirectory =
// Process the list of files found in the directory.
let fileEntries = Directory.GetFiles targetDirectory
for fileName in fileEntries do
processFile fileName
// Recurse into subdirectories of this directory.
let subdirectoryEntries = Directory.GetDirectories targetDirectory
for subdirectory in subdirectoryEntries do
processDirectory subdirectory
[<EntryPoint>]
let main args =
for path in args do
if File.Exists path then
// This path is a file
processFile path
elif Directory.Exists path then
// This path is a directory
processDirectory path
else
printfn $"{path} is not a valid file or directory."
0
' 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
Commenti
Il path
parametro è autorizzato a specificare informazioni relative o assolute sul percorso. Le informazioni relative sul percorso sono interpretate come relative alla directory di lavoro corrente.
Gli spazi finali vengono rimossi dalla fine del path
parametro prima di verificare se la directory esiste.
La distinzione tra maiuscole e minuscole del path
parametro corrisponde a quella del file system in cui è in esecuzione il codice. Ad esempio, non fa distinzione tra maiuscole e minuscole in NTFS (file system Windows predefinito) e fa distinzione tra maiuscole e minuscole nei file system Linux.
Se non si dispone almeno dell'autorizzazione di sola lettura per la directory, il Exists metodo restituirà false
.
Il Exists metodo restituisce false
se si verifica un errore durante il tentativo di determinare se il file specificato esiste. Questa situazione può verificarsi in situazioni che generano eccezioni, ad esempio il passaggio di un nome file con caratteri non validi o troppi caratteri, un errore o un disco mancante o se il chiamante non dispone dell'autorizzazione per leggere il file.