Directory.Exists(String) 方法
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
确定给定路径是否引用磁盘上的现有目录。
public:
static bool Exists(System::String ^ path);public static bool Exists(string path);static member Exists : string -> boolPublic Shared Function Exists (path As String) As Boolean参数
- path
- String
要测试的路径。
返回
true 如果 path 引用现有目录， false 则在尝试确定指定的目录是否存在时发生错误。
示例
下面的示例采用命令行上的文件或目录名称数组，确定它的名称类型，并相应地处理它。
// 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
注解
允许参数 path 指定相对路径或绝对路径信息。 相对路径信息解释为相对于当前工作目录。
在检查目录是否存在之前，将从参数末尾 path 删除尾随空格。
参数的 path 区分大小写对应于运行代码的文件系统。 例如，它在 NTFS（默认 Windows 文件系统）上不区分大小写，在 Linux 文件系统上区分大小写。
如果没有对目录的最小只读权限，该方法 Exists 将返回 false。
此方法 Exists 返回 false 在尝试确定指定文件是否存在时发生任何错误。 在引发异常的情况下，可能会引发异常，例如传递无效字符或字符过多、磁盘失败或缺失的文件名，或者调用方没有读取文件的权限。