Directory.EnumerateFiles Method (String, String)
Returns an enumerable collection of file names that match a search pattern in a specified path.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- path
-
Type:
System.String
The relative or absolute path to the directory to search. This string is not case-sensitive.
- searchPattern
-
Type:
System.String
The search string to match against the names of files in path. This parameter can contain a combination of valid literal path and wildcard (* and ?) characters (see Remarks), but doesn't support regular expressions.
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.
| Exception | Condition |
|---|---|
| ArgumentException | path is a zero-length string, contains only white space, or contains invalid characters. You can query for invalid characters by using the GetInvalidPathChars method. - or - searchPattern does not contain a valid pattern. |
| ArgumentNullException | path is null. -or- searchPattern is null. |
| 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. |
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 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".
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:
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. |
searchPattern cannot end in two periods ("..") or contain two periods ("..") followed by DirectorySeparatorChar or AltDirectorySeparatorChar, nor can it contain any invalid characters. You can query for invalid characters by using the 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 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 move them to a new directory. After the files are moved, they no longer exist in the original directory.
The following example enumerates the files in the specified directory that have a .txt extension, reads each line of the file, and displays the line if it contains the string "Europe".
Available since 10
.NET Framework
Available since 4.0
Silverlight
Available since 4.0
