System.IO.Directory.GetFileSystemEntries Method

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

Syntax

public static string[] GetFileSystemEntries (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 the names of files and directories 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 array of file the file names and directory names that match the specified search criteria, or an empty array if no files or directories are found.

Remarks

The order of the returned file and directory names is not guaranteed; use the erload:System.Array.Sort method if a specific sort order is required.

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.

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.

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.

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.

Requirements

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