Directory.EnumerateFileSystemEntries Method

Definition

Returns an enumerable collection of file-system entries that meet specified criteria.

Overloads

EnumerateFileSystemEntries(String)

Returns an enumerable collection of file names and directory names in a specified path.

EnumerateFileSystemEntries(String, String)

Returns an enumerable collection of file names and directory names that match a search pattern in a specified path.

EnumerateFileSystemEntries(String, String, EnumerationOptions)

Returns an enumerable collection of file names and directory names that match a search pattern and enumeration options in a specified path.

EnumerateFileSystemEntries(String, String, SearchOption)

Returns an enumerable collection of file names and directory names that match a search pattern in a specified path, and optionally searches subdirectories.

EnumerateFileSystemEntries(String)

Returns an enumerable collection of file names and directory names in a specified path.

public:
 static System::Collections::Generic::IEnumerable<System::String ^> ^ EnumerateFileSystemEntries(System::String ^ path);
public static System.Collections.Generic.IEnumerable<string> EnumerateFileSystemEntries (string path);
static member EnumerateFileSystemEntries : string -> seq<string>
Public Shared Function EnumerateFileSystemEntries (path As String) As IEnumerable(Of String)

Parameters

path
String

The relative or absolute path to the directory to search. This string is not case-sensitive.

Returns

An enumerable collection of file-system entries in the directory specified by path.

Exceptions

.NET Framework and .NET Core versions older than 2.1: path is a zero-length string, contains only white space, or contains invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

path is null.

path is invalid, such as referring to an unmapped drive.

path is a file name.

The specified path, file name, or combined exceed the system-defined maximum length.

The caller does not have the required permission.

The caller does not have the required permission.

Remarks

You can specify relative path information with the path parameter. Relative path information is interpreted as relative to the current working directory, which you can determine by using the GetCurrentDirectory method.

The EnumerateFileSystemEntries and GetFileSystemEntries methods differ as follows: When you use EnumerateFileSystemEntries, you can start enumerating the collection of entries before the whole collection is returned; when you use GetFileSystemEntries, you must wait for the whole array of entries to be returned before you can access the array. Therefore, when you are working with many files and directories, EnumerateFileSystemEntries can be more efficient.

The returned collection is not cached; each call to the GetEnumerator on the collection will start a new enumeration.

Applies to

EnumerateFileSystemEntries(String, String)

Returns an enumerable collection of file names and directory names that match a search pattern in a specified path.

public:
 static System::Collections::Generic::IEnumerable<System::String ^> ^ EnumerateFileSystemEntries(System::String ^ path, System::String ^ searchPattern);
public static System.Collections.Generic.IEnumerable<string> EnumerateFileSystemEntries (string path, string searchPattern);
static member EnumerateFileSystemEntries : string * string -> seq<string>
Public Shared Function EnumerateFileSystemEntries (path As String, searchPattern As String) As IEnumerable(Of String)

Parameters

path
String

The relative or absolute path to the directory to search. This string is not case-sensitive.

searchPattern
String

The search string to match against the names of file-system entries in path. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters, but it doesn't support regular expressions.

Returns

An enumerable collection of file-system entries in the directory specified by path and that match the specified search pattern.

Exceptions

.NET Framework and .NET Core versions older than 2.1: path is a zero-length string, contains only white space, or contains invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

-or-

searchPattern does not contain a valid pattern.

path is null.

-or-

searchPattern is null.

path is invalid, such as referring to an unmapped drive.

path is a file name.

The specified path, file name, or combined exceed the system-defined maximum length.

The caller does not have the required permission.

The caller does not have the required permission.

Remarks

searchPattern can be a combination of literal and wildcard characters, but it doesn't support regular expressions. The following wildcard specifiers are permitted in searchPattern.

Wildcard specifier Matches
* (asterisk) Zero or more characters in that position.
? (question mark) Exactly one character in that position.

Characters other than the wildcard are literal characters. For example, the searchPattern string "*t" searches for all names in path ending with the letter "t". The searchPattern string "s*" searches for all names in path beginning with the letter "s".

Note

When you use the asterisk wildcard character in a searchPattern such as "*.txt", the number of characters in the specified extension affects the search as follows:

  • If the specified extension is exactly three characters long, the method returns files with extensions that begin with the specified extension. For example, "*.xls" returns both "book.xls" and "book.xlsx".
  • In all other cases, the method returns files that exactly match the specified extension. For example, "*.ai" returns "file.ai" but not "file.aif".

When you use the question mark wildcard character, this method returns only files that match the specified file extension. For example, given two files, "file1.txt" and "file1.txtother", in a directory, a search pattern of "file?.txt" returns just the first file, whereas a search pattern of "file*.txt" returns both files.

searchPattern cannot end in two periods ("..") or contain two periods ("..") followed by DirectorySeparatorChar or AltDirectorySeparatorChar, nor can it contain any invalid characters. You can query for invalid characters by using the GetInvalidPathChars method.

You can specify relative path information with the path parameter. Relative path information is interpreted as relative to the current working directory, which you can determine by using the GetCurrentDirectory method.

The EnumerateFileSystemEntries and GetFileSystemEntries methods differ as follows: When you use EnumerateFileSystemEntries, you can start enumerating the collection of entries before the whole collection is returned; when you use GetFileSystemEntries, you must wait for the whole array of entries to be returned before you can access the array. Therefore, when you are working with many files and directories, EnumerateFileSystemEntries can be more efficient.

The returned collection is not cached; each call to the GetEnumerator on the collection will start a new enumeration.

Applies to

EnumerateFileSystemEntries(String, String, EnumerationOptions)

Returns an enumerable collection of file names and directory names that match a search pattern and enumeration options in a specified path.

public:
 static System::Collections::Generic::IEnumerable<System::String ^> ^ EnumerateFileSystemEntries(System::String ^ path, System::String ^ searchPattern, System::IO::EnumerationOptions ^ enumerationOptions);
public static System.Collections.Generic.IEnumerable<string> EnumerateFileSystemEntries (string path, string searchPattern, System.IO.EnumerationOptions enumerationOptions);
static member EnumerateFileSystemEntries : string * string * System.IO.EnumerationOptions -> seq<string>
Public Shared Function EnumerateFileSystemEntries (path As String, searchPattern As String, enumerationOptions As EnumerationOptions) As IEnumerable(Of String)

Parameters

path
String

The relative or absolute path to the directory to search. This string is not case-sensitive.

searchPattern
String

The search string to match against the names of subdirectories in path. This parameter can contain a combination of valid literal and wildcard characters, but it doesn't support regular expressions.

enumerationOptions
EnumerationOptions

An object that describes the search and enumeration configuration to use.

Returns

An enumerable collection of file-system entries in the directory specified by path, that match the specified search pattern and the specified enumeration options.

Exceptions

.NET Framework and .NET Core versions older than 2.1: path is a zero-length string, contains only white space, or contains invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

-or-

searchPattern does not contain a valid pattern.

path is null.

-or-

searchPattern is null.

searchOption is not a valid SearchOption value.

path is invalid, such as referring to an unmapped drive.

path is a file name.

The specified path, file name, or combined exceed the system-defined maximum length.

The caller does not have the required permission.

The caller does not have the required permission.

Remarks

searchPattern can be a combination of literal and wildcard characters, but it doesn't support regular expressions. The following wildcard specifiers are permitted in searchPattern.

Wildcard specifier Matches
* (asterisk) Zero or more characters in that position.
? (question mark) Exactly one character in that position.

Characters other than the wildcard are literal characters. For example, the searchPattern string "*t" searches for all names in path ending with the letter "t". The searchPattern string "s*" searches for all names in path beginning with the letter "s".

Note

When you use the asterisk wildcard character in a searchPattern such as "*.txt", the number of characters in the specified extension affects the search as follows:

  • If the specified extension is exactly three characters long, the method returns files with extensions that begin with the specified extension. For example, "*.xls" returns both "book.xls" and "book.xlsx".
  • In all other cases, the method returns files that exactly match the specified extension. For example, "*.ai" returns "file.ai" but not "file.aif".

When you use the question mark wildcard character, this method returns only files that match the specified file extension. For example, given two files, "file1.txt" and "file1.txtother", in a directory, a search pattern of "file?.txt" returns just the first file, whereas a search pattern of "file*.txt" returns both files.

searchPattern cannot end in two periods ("..") or contain two periods ("..") followed by DirectorySeparatorChar or AltDirectorySeparatorChar, nor can it contain any invalid characters. You can query for invalid characters by using the GetInvalidPathChars method.

You can specify relative path information with the path parameter. Relative path information is interpreted as relative to the current working directory, which you can determine by using the GetCurrentDirectory method.

The EnumerateFileSystemEntries and GetFileSystemEntries methods differ as follows: When you use EnumerateFileSystemEntries, you can start enumerating the collection of entries before the whole collection is returned; when you use GetFileSystemEntries, you must wait for the whole array of entries to be returned before you can access the array. Therefore, when you are working with many files and directories, EnumerateFileSystemEntries can be more efficient.

The returned collection is not cached; each call to the GetEnumerator on the collection will start a new enumeration.

Applies to

EnumerateFileSystemEntries(String, String, SearchOption)

Returns an enumerable collection of file names and directory names that match a search pattern in a specified path, and optionally searches subdirectories.

public:
 static System::Collections::Generic::IEnumerable<System::String ^> ^ EnumerateFileSystemEntries(System::String ^ path, System::String ^ searchPattern, System::IO::SearchOption searchOption);
public static System.Collections.Generic.IEnumerable<string> EnumerateFileSystemEntries (string path, string searchPattern, System.IO.SearchOption searchOption);
static member EnumerateFileSystemEntries : string * string * System.IO.SearchOption -> seq<string>
Public Shared Function EnumerateFileSystemEntries (path As String, searchPattern As String, searchOption As SearchOption) As IEnumerable(Of String)

Parameters

path
String

The relative or absolute path to the directory to search. This string is not case-sensitive.

searchPattern
String

The search string to match against file-system entries in path. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters, but it doesn't support regular expressions.

searchOption
SearchOption

One of the enumeration values that specifies whether the search operation should include only the current directory or should include all subdirectories. The default value is TopDirectoryOnly.

Returns

An enumerable collection of file-system entries in the directory specified by path and that match the specified search pattern and option.

Exceptions

.NET Framework and .NET Core versions older than 2.1: path is a zero-length string, contains only white space, or contains invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

-or-

searchPattern does not contain a valid pattern.

path is null.

-or-

searchPattern is null.

searchOption is not a valid SearchOption value.

path is invalid, such as referring to an unmapped drive.

path is a file name.

The specified path, file name, or combined exceed the system-defined maximum length.

The caller does not have the required permission.

The caller does not have the required permission.

Remarks

searchPattern can be a combination of literal and wildcard characters, but it doesn't support regular expressions. The following wildcard specifiers are permitted in searchPattern.

Wildcard specifier Matches
* (asterisk) Zero or more characters in that position.
? (question mark) Exactly one character in that position.

Characters other than the wildcard are literal characters. For example, the searchPattern string "*t" searches for all names in path ending with the letter "t". The searchPattern string "s*" searches for all names in path beginning with the letter "s".

Note

When you use the asterisk wildcard character in a searchPattern such as "*.txt", the number of characters in the specified extension affects the search as follows:

  • If the specified extension is exactly three characters long, the method returns files with extensions that begin with the specified extension. For example, "*.xls" returns both "book.xls" and "book.xlsx".
  • In all other cases, the method returns files that exactly match the specified extension. For example, "*.ai" returns "file.ai" but not "file.aif".

When you use the question mark wildcard character, this method returns only files that match the specified file extension. For example, given two files, "file1.txt" and "file1.txtother", in a directory, a search pattern of "file?.txt" returns just the first file, whereas a search pattern of "file*.txt" returns both files.

searchPattern cannot end in two periods ("..") or contain two periods ("..") followed by DirectorySeparatorChar or AltDirectorySeparatorChar, nor can it contain any invalid characters. You can query for invalid characters by using the GetInvalidPathChars method.

You can specify relative path information with the path parameter. Relative path information is interpreted as relative to the current working directory, which you can determine by using the GetCurrentDirectory method.

The EnumerateFileSystemEntries and GetFileSystemEntries methods differ as follows: When you use EnumerateFileSystemEntries, you can start enumerating the collection of entries before the whole collection is returned; when you use GetFileSystemEntries, you must wait for the whole array of entries to be returned before you can access the array. Therefore, when you are working with many files and directories, EnumerateFileSystemEntries can be more efficient.

The returned collection is not cached; each call to the GetEnumerator on the collection will start a new enumeration.

Applies to