Directory.EnumerateFiles Method

Definition

Namespace:

System.IO

Assemblies:

netstandard.dll, System.Runtime.dll

Returns an enumerable collection of full file names that meet specified criteria.

Overloads

EnumerateFiles(String, String, SearchOption)	Returns an enumerable collection of full file names that match a search pattern in a specified path, and optionally searches subdirectories.
EnumerateFiles(String, String, EnumerationOptions)	Returns an enumerable collection of full file names that match a search pattern and enumeration options in a specified path, and optionally searches subdirectories.
EnumerateFiles(String)	Returns an enumerable collection of full file names in a specified path.
EnumerateFiles(String, String)	Returns an enumerable collection of full file names that match a search pattern in a specified path.

EnumerateFiles(String, String, SearchOption)

Source:

Directory.cs

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

C#

public static System.Collections.Generic.IEnumerable<string> EnumerateFiles(string path, string searchPattern, System.IO.SearchOption searchOption);

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 files 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

IEnumerable<String>

An enumerable collection of the full names (including paths) for the files in the directory specified by path and that match the specified search pattern and search option.

Exceptions

ArgumentException

.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.

ArgumentNullException

path is null.

-or-

searchPattern is null.

ArgumentOutOfRangeException

searchOption is not a valid SearchOption value.

DirectoryNotFoundException

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

IOException

path is a file name.

PathTooLongException

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

SecurityException

The caller does not have the required permission.

UnauthorizedAccessException

The caller does not have the required permission.

Examples

The following example shows how to retrieve all the text files in a directory and its subdirectories, and move them to a new directory. After the files are moved, they no longer exist in the original directories.

C#

using System;
using System.IO;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            string sourceDirectory = @"C:\current";
            string archiveDirectory = @"C:\archive";

            try
            {
                var txtFiles = Directory.EnumerateFiles(sourceDirectory, "*.txt", SearchOption.AllDirectories);

                foreach (string currentFile in txtFiles)
                {
                    string fileName = currentFile.Substring(sourceDirectory.Length + 1);
                    Directory.Move(currentFile, Path.Combine(archiveDirectory, fileName));
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}

The following example recursively enumerates all files that have the extension .txt, reads each line of the file, and displays the line if it contains the string "Microsoft".

C#

using System;
using System.IO;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        try
        {
            // Set a variable to the My Documents path.
            string docPath =
            Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

            var files = from file in Directory.EnumerateFiles(docPath, "*.txt", SearchOption.AllDirectories)
                        from line in File.ReadLines(file)
                        where line.Contains("Microsoft")
                        select new
                        {
                            File = file,
                            Line = line
                        };

            foreach (var f in files)
            {
                Console.WriteLine($"{f.File}\t{f.Line}");
            }
            Console.WriteLine($"{files.Count().ToString()} files found.");
        }
        catch (UnauthorizedAccessException uAEx)
        {
            Console.WriteLine(uAEx.Message);
        }
        catch (PathTooLongException pathEx)
        {
            Console.WriteLine(pathEx.Message);
        }
    }
}

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

.NET Framework only: When you use the asterisk wildcard character in searchPattern and you specify a three-character file extension, for example, "*.txt", this method also returns files with extensions that begin with the specified extension. For example, the search pattern "*.xls" returns both "book.xls" and "book.xlsx". This behavior only occurs if an asterisk is used in the search pattern and the file extension provided is exactly three characters. If you use the question mark wildcard character somewhere in the search pattern, this method returns only files that match the specified file extension exactly. The following table depicts this anomaly in .NET Framework.

Files in directory	Search pattern	.NET 5+ returns	.NET Framework returns
file.ai, file.aif	*.ai	file.ai	file.ai
book.xls, book.xlsx	*.xls	book.xls	book.xls, book.xlsx
ello.txt, hello.txt, hello.txtt	?ello.txt	hello.txt	hello.txt

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

The returned collection is not cached. Each call to the GetEnumerator on the collection starts a new enumeration.

EnumerateFiles(String, String, EnumerationOptions)

Source:

Directory.cs

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

C#

public static System.Collections.Generic.IEnumerable<string> EnumerateFiles(string path, string searchPattern, System.IO.EnumerationOptions enumerationOptions);

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 files in path. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters, but it doesn't support regular expressions.

enumerationOptions

EnumerationOptions

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

Returns

IEnumerable<String>

An enumerable collection of the full names (including paths) for the files in the directory specified by path and that match the specified search pattern and enumeration options.

Exceptions

ArgumentException

.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.

ArgumentNullException

path is null.

-or-

searchPattern is null.

ArgumentOutOfRangeException

enumerationOptions is not a valid EnumerationOptions value.

DirectoryNotFoundException

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

IOException

path is a file name.

PathTooLongException

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

UnauthorizedAccessException

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

.NET Framework only: When you use the asterisk wildcard character in searchPattern and you specify a three-character file extension, for example, "*.txt", this method also returns files with extensions that begin with the specified extension. For example, the search pattern "*.xls" returns both "book.xls" and "book.xlsx". This behavior only occurs if an asterisk is used in the search pattern and the file extension provided is exactly three characters. If you use the question mark wildcard character somewhere in the search pattern, this method returns only files that match the specified file extension exactly. The following table depicts this anomaly in .NET Framework.

Files in directory	Search pattern	.NET 5+ returns	.NET Framework returns
file.ai, file.aif	*.ai	file.ai	file.ai
book.xls, book.xlsx	*.xls	book.xls	book.xls, book.xlsx
ello.txt, hello.txt, hello.txtt	?ello.txt	hello.txt	hello.txt

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

The returned collection is not cached. Each call to the GetEnumerator on the collection starts a new enumeration.

EnumerateFiles(String)

Source:

Directory.cs

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

C#

public static System.Collections.Generic.IEnumerable<string> EnumerateFiles(string path);

Parameters

path

String

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

Returns

IEnumerable<String>

An enumerable collection of the full names (including paths) for the files in the directory specified by path.

Exceptions

ArgumentException

.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.

ArgumentNullException

path is null.

DirectoryNotFoundException

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

IOException

path is a file name.

PathTooLongException

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

SecurityException

The caller does not have the required permission.

UnauthorizedAccessException

The caller does not have the required permission.

Examples

The following example shows how to retrieve all the files in a directory and move them to a new directory. After the files are moved, they no longer exist in the original directory.

C#

using System;
using System.IO;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            string sourceDirectory = @"C:\current";
            string archiveDirectory = @"C:\archive";

            try
            {
                var txtFiles = Directory.EnumerateFiles(sourceDirectory);

                foreach (string currentFile in txtFiles)
                {
                    string fileName = currentFile.Substring(sourceDirectory.Length + 1);
                    Directory.Move(currentFile, Path.Combine(archiveDirectory, fileName));
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}

The following example enumerates the files in the specified directory, reads each line of the file, and displays the line if it contains the string "Europe".

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        try
        {
            // LINQ query for all files containing the word 'Europe'.
            var files = from file in
                Directory.EnumerateFiles(@"\\archives1\library\")
                where file.ToLower().Contains("europe")
                select file;

            foreach (var file in files)
            {
                Console.WriteLine("{0}", file);
            }
            Console.WriteLine("{0} files found.", files.Count<string>().ToString());
        }
        catch (UnauthorizedAccessException UAEx)
        {
            Console.WriteLine(UAEx.Message);
        }
        catch (PathTooLongException PathEx)
        {
            Console.WriteLine(PathEx.Message);
        }
    }
}

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

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

EnumerateFiles(String, String)

Source:

Directory.cs

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

C#

public static System.Collections.Generic.IEnumerable<string> EnumerateFiles(string path, string searchPattern);

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 files in path. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters, but it doesn't support regular expressions.

Returns

IEnumerable<String>

An enumerable collection of the full names (including paths) for the files in the directory specified by path and that match the specified search pattern.

Exceptions

ArgumentException

.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.

ArgumentNullException

path is null.

-or-

searchPattern is null.

DirectoryNotFoundException

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

IOException

path is a file name.

PathTooLongException

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

SecurityException

The caller does not have the required permission.

UnauthorizedAccessException

The caller does not have the required permission.

Examples

The following example shows how to retrieve all the text files in a directory and move them to a new directory. After the files are moved, they no longer exist in the original directory.

C#

using System;
using System.IO;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            string sourceDirectory = @"C:\current";
            string archiveDirectory = @"C:\archive";

            try
            {
                var txtFiles = Directory.EnumerateFiles(sourceDirectory, "*.txt");

                foreach (string currentFile in txtFiles)
                {
                    string fileName = currentFile.Substring(sourceDirectory.Length + 1);
                    Directory.Move(currentFile, Path.Combine(archiveDirectory, fileName));
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }
}

The following example enumerates the files in the specified directory that have a ".txt" extension, reads each line of the file, and displays the line if it contains the string "Europe".

C#

using System;
using System.Linq;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        try
        {
            // LINQ query for all .txt files containing the word 'Europe'.
            var files = from file in Directory.EnumerateFiles(@"\\archives1\library\", "*.txt")
                where file.ToLower().Contains("europe")
                select file;

            foreach (var file in files)
            {
                Console.WriteLine("{0}", file);
            }
            Console.WriteLine("{0} files found.", files.Count<string>().ToString());
        }
            
        catch (UnauthorizedAccessException UAEx)
        {
            Console.WriteLine(UAEx.Message);
        }
        catch (PathTooLongException PathEx)
        {
            Console.WriteLine(PathEx.Message);
        }
    }
}

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

.NET Framework only: When you use the asterisk wildcard character in searchPattern and you specify a three-character file extension, for example, "*.txt", this method also returns files with extensions that begin with the specified extension. For example, the search pattern "*.xls" returns both "book.xls" and "book.xlsx". This behavior only occurs if an asterisk is used in the search pattern and the file extension provided is exactly three characters. If you use the question mark wildcard character somewhere in the search pattern, this method returns only files that match the specified file extension exactly. The following table depicts this anomaly in .NET Framework.

Files in directory	Search pattern	.NET 5+ returns	.NET Framework returns
file.ai, file.aif	*.ai	file.ai	file.ai
book.xls, book.xlsx	*.xls	book.xls	book.xls, book.xlsx
ello.txt, hello.txt, hello.txtt	?ello.txt	hello.txt	hello.txt

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

The returned collection is not cached. Each call to the GetEnumerator on the collection starts a new enumeration.