Directory.EnumerateFiles Method (String, String, SearchOption)
Returns an enumerable collection of file 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> EnumerateFiles( 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 enumeration values 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 the full names (including paths) for the files in the directory specified by path and that match the specified search pattern and option.
| Exception | Condition |
|---|---|
| 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. |
Characters other than the wildcard specifiers represent themselves. For example, the searchPattern string "*t" searches for all names in path that end with the letter "t". The searchPattern string "s*" searches for all names in path that begin with the letter "s".
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.
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.
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 a .txt extension, reads each line of the file, and displays the line if it contains the string "Microsoft".
using System; using System.IO; using System.Linq; class Program { static void Main(string[] args) { try { var files = from file in Directory.EnumerateFiles(@"c:\", "*.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("{0}\t{1}", f.File, f.Line); } Console.WriteLine("{0} files found.", files.Count().ToString()); } catch (UnauthorizedAccessException UAEx) { Console.WriteLine(UAEx.Message); } catch (PathTooLongException PathEx) { Console.WriteLine(PathEx.Message); } } }
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
