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DirectoryInfo.EnumerateDirectories Method (String, SearchOption)

Returns an enumerable collection of directory information that matches a specified search pattern and search subdirectory option.

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

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

Parameters

searchPattern
Type: System.String

The search string to match against the names of directories. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters (see Remarks), but doesn't support regular expressions. The default pattern is "*", which returns all files.

searchOption
Type: System.IO.SearchOption

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

Return Value

Type: System.Collections.Generic.IEnumerable<DirectoryInfo>
An enumerable collection of directories that matches searchPattern and searchOption.

ExceptionCondition
ArgumentNullException

searchPattern is null.

ArgumentOutOfRangeException

searchOption is not a valid SearchOption value.

DirectoryNotFoundException

The path encapsulated in the DirectoryInfo object is invalid (for example, it is on an unmapped drive).

SecurityException

The caller does not have the required permission.

searchPattern can be a combination of literal and wildcard characters, but 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)

Zero or one character in that position.

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

The EnumerateDirectories and GetDirectories methods differ as follows:

Therefore, when you are working with many files and directories, EnumerateDirectories can be more efficient.

This method pre-populates the values of the following DirectoryInfo properties:

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

The following example, starting from a specified directory, uses this method and the EnumerateFiles method to enumerate the files and directories within the start directory and display details of any files over 10 MB in size.

using System;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        DirectoryInfo diTop = new DirectoryInfo(@"d:\");
        try
        {
            foreach (var fi in diTop.EnumerateFiles())
            {
                try
                {
                    // Display each file over 10 MB; 
                    if (fi.Length > 10000000)
                    {
                        Console.WriteLine("{0}\t\t{1}", fi.FullName, fi.Length.ToString("N0"));
                    }
                }
                catch (UnauthorizedAccessException UnAuthTop)
                {
                    Console.WriteLine("{0}", UnAuthTop.Message);
                }
            }

            foreach (var di in diTop.EnumerateDirectories("*"))
            {
                try
                {
                    foreach (var fi in di.EnumerateFiles("*", SearchOption.AllDirectories))
                    {
                        try
                        {
                            // Display each file over 10 MB; 
                            if (fi.Length > 10000000)
                            {
                                Console.WriteLine("{0}\t\t{1}",  fi.FullName, fi.Length.ToString("N0"));
                            }
                        }
                        catch (UnauthorizedAccessException UnAuthFile)
                        {
                            Console.WriteLine("UnAuthFile: {0}", UnAuthFile.Message);
                        }
                    }
                }
                catch (UnauthorizedAccessException UnAuthSubDir)
                {
                    Console.WriteLine("UnAuthSubDir: {0}", UnAuthSubDir.Message);
                }
            }
        }
        catch (DirectoryNotFoundException DirNotFound)
        {
            Console.WriteLine("{0}", DirNotFound.Message);
        }
        catch (UnauthorizedAccessException UnAuthDir)
        {
            Console.WriteLine("UnAuthDir: {0}", UnAuthDir.Message);
        }
        catch (PathTooLongException LongPath)
        {
            Console.WriteLine("{0}", LongPath.Message);
        }
    }
}

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4
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