Directory.Exists(String) 方法

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

參數

傳回

true 如果 path 指的是現有目錄; false 若該目錄不存在，或在嘗試判斷指定目錄是否存在時發生錯誤。

範例

以下範例將命令列中的檔案或目錄名稱陣列，判定其名稱類型，並適當處理。

// 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

備註

path參數允許指定相對或絕對路徑資訊。 相對路徑資訊會被解讀為相對於目前工作目錄的相對於。

在檢查目錄是否存在前，會先從參數末尾 path 移除尾部的空格。

參數的 path 大小寫區分對應於執行程式碼的檔案系統。 例如，在 NTFS（預設 Windows 檔案系統）上它是不區分大小寫的，在 Linux 檔案系統上則是不區分大小寫。

若你對該目錄沒有至少只讀權限，該 Exists 方法將回傳 false。

若在嘗試判斷指定檔案是否存在時發生錯誤，該 Exists 方法會回傳 false 。 這種情況可能發生在產生例外的情況，例如傳入無效字元或過多字元的檔名、磁碟故障或遺失，或呼叫者無權讀取該檔案。

另請參閱

• DirectoryInfo
• 檔案和數據流 I/O
• 如何：從檔案讀取文字
• 如何：將文字寫入檔案