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Directory.EnumerateDirectories Method (String, String, SearchOption)

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

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)

public static IEnumerable<string> EnumerateDirectories(
	string path,
	string searchPattern,
	SearchOption searchOption
)

Parameters

path
Type: System.String
The directory to search.
searchPattern
Type: System.String
The search string to match against the names of directories in path.
searchOption
Type: System.IO.SearchOption
One of the values of the SearchOption enumeration that specifies whether the search operation should include only the current directory or should include all subdirectories.
The default value is TopDirectoryOnly.

Return Value

Type: System.Collections.Generic.IEnumerable<String>
An enumerable collection of directory names in the directory specified by path and that match searchPattern and searchOption.

ExceptionCondition
ArgumentException

path is a zero-length string, contains only white space, or contains invalid characters as defined by GetInvalidPathChars.

- 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. For example, on Windows-based platforms, paths must be less than 248 characters and file names must be less than 260 characters.

SecurityException

The caller does not have the required permission.

UnauthorizedAccessException

The caller does not have the required permission.

The following wildcard specifiers are permitted in the searchPattern parameter.

Wildcard character

Description

*

Zero or more characters.

?

Exactly one character.

You can specify relative or absolute path information in 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 returned directory names are prefixed with the value you provided in the path parameter. For example, if you provide a relative path in the path parameter, the returned directory names will contain a relative path.

The EnumerateDirectories and GetDirectories methods differ as follows: When you use EnumerateDirectories, you can start enumerating the collection of names before the whole collection is returned; when you use GetDirectories, 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, EnumerateDirectories can be more efficient.

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

The following example enumerates directories in a specified path that match a specified search pattern. It uses the SearchOption parameter to specify that all subdirectories should be included in the search.


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

class Program
{

    private static void Main(string[] args)
    {
        try
        {
            string dirPath = @"\\archives\2009\reports";

            // LINQ query.
            var dirs = from dir in 
                     Directory.EnumerateDirectories(dirPath, "dv_*",
                     	SearchOption.AllDirectories)
                       select dir;

            // Show results.
            foreach (var dir in dirs)
            {
                // Remove path information from string.
                Console.WriteLine("{0}", 
                    dir.Substring(dir.LastIndexOf("\\") + 1));

            }
            Console.WriteLine("{0} directories found.", 
                dirs.Count<string>().ToString());

            // Optionally create a List collection.
            List<string> workDirs = new List<string>(dirs);
        }
        catch (UnauthorizedAccessException UAEx)
        {
            Console.WriteLine(UAEx.Message);
        }
        catch (PathTooLongException PathEx)
        {
            Console.WriteLine(PathEx.Message);
        }
    }
}


.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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