Directory.Exists(String) 方法
定义
重要
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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);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
如果 path 指向现有目录，则为 true；如果该目录不存在或者在尝试确定指定目录是否存在时出错，则为 false。
示例
以下示例在命令行上采用文件或目录名称数组，确定其名称类型，并对其进行适当处理。
// 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
注解
允许 path 参数指定相对或绝对路径信息。 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， path 将从参数末尾删除尾随空格。
参数的 path 区分大小写对应于运行代码的文件系统的区分大小写。 例如，它在 NTFS 上不区分大小写， (默认 Windows 文件系统) ，Linux 文件系统上区分大小写。
如果对目录没有最低只读权限，则 Exists 方法将返回 false。
如果在尝试确定指定文件是否存在时发生任何错误，则 Exists 该方法将返回 false 。 在引发异常的情况下，可能会发生这种情况，例如传递包含无效字符或太多字符的文件名、磁盘失败或缺失，或者调用方没有读取文件的权限。
