System.IO.Directory.EnumerateFileSystemEntries Method

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

Syntax

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

Parameters

path
The relative or absolute path to the directory to search. This string is not case-sensitive.
searchPattern
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 (see Remarks), but doesn't support regular expressions.
searchOption
One of the enumeration values that specifies whether the search operation should include only the current directory or should include all subdirectories.

Returns

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

Remarks

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

* (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 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".

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

The erload:System.IO.Directory.EnumerateFileSystemEntries and erload:System.IO.Directory.GetFileSystemEntries methods differ as follows: When you use erload:System.IO.Directory.EnumerateFileSystemEntries, you can start enumerating the collection of entries before the whole collection is returned; when you use erload:System.IO.Directory.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, erload:System.IO.Directory.EnumerateFiles can be more efficient.

The returned collection is not cached; each call to the IEnumerable`1.GetEnumerator on the collection will start a new enumeration.

Requirements

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 4.0.0.0