Directory.Exists(String) Directory.Exists(String) Directory.Exists(String) Directory.Exists(String) Method

定義

判斷指定路徑是否參考磁碟上的現有目錄。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

參數

path
String String String String

要測試的路徑。The path to test.

傳回

如果 path 會參考現有的目錄,則為 true;如果目錄不存在,或嘗試判斷指定的目錄是否存在時發生錯誤,則為 falsetrue 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.

範例

下列範例會在命令列上的檔案或目錄名稱的陣列,決定何種名稱,並適當地加以處理。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
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 'Main


    ' 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 'ProcessDirectory

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

備註

path參數可以指定相對或絕對路徑資訊。The path parameter is permitted to specify relative or absolute path information. 相對於目前工作目錄,會解譯相對路徑的資訊。Relative path information is interpreted as relative to the current working directory.

從結尾會移除尾端空格path再檢查目錄是否存在的參數。Trailing spaces are removed from the end of the path parameter before checking whether the directory exists.

path參數不區分大小寫。The path parameter is not case-sensitive.

如果您不需要在目錄中,最小唯讀權限Exists方法會傳回falseIf you do not have at a minimum read-only permission to the directory, the Exists method will return false.

Exists方法會傳回false如果嘗試判斷指定的檔案是否存在時發生任何錯誤。The Exists method returns false if any error occurs while trying to determine if the specified file exists. 可能發生這種情況下,會引發例外狀況,例如傳遞檔名無效的字元或太多字元、 失敗或遺失的磁碟,或如果呼叫端沒有讀取檔案的權限。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.

安全性

FileIOPermission
用於讀取檔案。for reading files. 相關聯的列舉型別: ReadAssociated enumeration: Read

適用於

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