This question already has answers here:
File.Exists - Wrong?
(3 answers)
Check if file or folder by given path exists
(5 answers)
Closed 8 months ago.
I am trying to list all the files in the Documents folder using an absolute path in C# using this C:\\Users\\USER\\Documents, I check first if the path exists and then try to list all the files in that location but my conditional structure is returning false while the path exists on my machine, I guess the double slash is for escaping the single slash characters. Why is my code returning false for the File.Exists(path) and the path does exist on my machine as C:\Users\USER\Documents
public class Solution
{
private static string[] files;
static void Main(string[] args)
{
string path = "C:\\Users\\USER\\Documents";
//check if the path exists
if (File.Exists(path))
{
//list all the files in the path
files = Directory.GetFiles(path);
//check if the count is greater than 0
if (files.Length > 0)
{
foreach (string r in files)
{
Console.WriteLine(r);
};
}
else
{
Console.WriteLine("This file location is empty");
}
}
else
{
//this section executes so the path is returning false
Console.WriteLine("Path does not exist");
}
}
}
File.Exists checks if a file exists, NOT a directory - it is the reason you get false.
To check if a directory exists use Directory.Exists:
if (Directory.Exists(path))
{
// your code
}
Related
I want to pass a list of directories to my C# console application as arguments which may be relative paths based on the current working directory, or contain drive letters and/or wildcards. E.g.:
myApp.exe someDir another\dir dirs\with\wild*cards* ..\..\a\relative\dir C:\an\absolute\dir\with\wild*cards*
So far I've come up with this:
static void Main(string[] args)
{
List<string> directories = new List<string>();
foreach (string arg in args)
{
if (Directory.Exists(arg))
{
// 'arg' by itself is a valid directory, and must not contain any wildcards
// just add it to 'directories'
directories.Add(arg);
}
else
{
// 'arg' must either be a non-existant directory or invalid directory name,
// or else it contains wildcard(s). Find all matching directory names, starting
// at the current directory (assuming 'arg' might be a relative path), and add
// all matching directory names to 'directories'.
string[] dirs = Directory.GetDirectories(Directory.GetCurrentDirectory(), arg, SearchOption.TopDirectoryOnly);
directories.AddRange(dirs);
}
}
Console.WriteLine("Full list of directories specified by the command line args:");
foreach (string dir in directories)
{
Console.WriteLine(" " + dir);
}
// Now go do what I want to do for each of these directories...
}
This works great for someDir, another\dir, and dirs\with\wild*cards*, but won't work for ..\..\a\relative\dir or C:\an\abolute\dir\with\wild*cards*. For the relative dir, Directory.GetDirectories() throws a System.ArgumentException saying "Search pattern cannot contain '..' to move up directories and can be contained only internally in file/directory names, as in 'a..b'." For the drive-letter-based directory, it throws a System.ArgumentException saying "Second path fragment must not be a drive or UNC name."
How can I handle the ".." and drive letters? This has to be a solved problem, but I can't find examples of such for C#.
"Bonus question": My above code also doesn't handle a\path\with\wild*cards*\in\anything\other\than\the\top\directory. Any easy way to handle that too?
Couple of observations:
1) To check if path absolute or relative - you can use Path.IsRooted()
2) To resolve path with ".." to absolute path (be it relative or absolute) you can use:
path = new Uri(Path.Combine(Directory.GetCurrentDirectory(), path)).AbsolutePath;
Routing it though Uri expands those dots. Path.GetFullPath will fail in case of wildcards, but Uri will not.
3) To check if path contains wildcards you can just do path.Contains("*") || path.Contains("?") since both of those characters are not valid path chars, so cannot be present in a context other than being wildcards.
4) To resolve wildcard in absolute path (and match your "bonus" requirement) you need to find out first directory which does not contain wildcard. So you basically need to split path into to parts - before first wildcard and after first wildcard. For example:
C:\an\abolute\dir\with\wild*cards*
Path before wildcard is C:\an\abolute\dir\with, after (and including) wildcard: wild*cards*.
C:\an\abolu*e\dir\with\wild*cards*
Path before first wildcard: C:\an, after: abolu*e\dir\with\wild*cards*. There are different ways to do that of course, easiest I think is regex:
#"[\\/](?=[^\\/]*[\*?])"
It basically matches directory separator, but only if it is followed by 0 or more charactres which are NOT directory separators, then followed by wildcard symbol.
Combining this all together we have:
static IEnumerable<string> ResolveDirectories(string path) {
if (path.Contains("*") || path.Contains("?")) {
// we have a wildcard,
// resolve it to absolute path if necessary
if (!Path.IsPathRooted(path))
path = Path.Combine(Directory.GetCurrentDirectory(), path);
// resolve .. stuff if any
path = new Uri(Path.Combine(Directory.GetCurrentDirectory(), path)).AbsolutePath;
// split with regex above, only on first match (2 parts)
var parts = new Regex(#"[\\/](?=[^\\/]*[\*?])").Split(path, 2);
var searchRoot = parts[0];
var searchPatterns = parts[1].Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
foreach (var dir in ResolveWildcards(searchRoot, searchPatterns))
yield return dir;
}
else {
// this should work with "../.." type of paths too, will resolve relative to current directory
// so no processing is necessary
if (Directory.Exists(path)) {
yield return path;
}
else {
// invalid directory?
}
}
}
static IEnumerable<string> ResolveWildcards(string searchRoot, string [] searchPatterns) {
// if we have path C:\an\abolu*e\dir\with\wild*cards*
// search root is C:\an
// and patterns are: [abolu*e, dir, with, wild*cards*]
if (Directory.Exists(searchRoot)) {
// use next pattern to search in a search root
var next = searchPatterns[0];
// leave the rest for recursion
var rest = searchPatterns.Skip(1).ToArray();
foreach (var dir in Directory.EnumerateDirectories(searchRoot, next, SearchOption.AllDirectories)) {
// if nothing left (last pattern) - return it
if (rest.Length == 0)
yield return dir;
else {
// otherwise search with rest patterns in freshly found directory
foreach (var sub in ResolveWildcards(dir, rest))
yield return sub;
}
}
}
}
This is not properly tested, so take care.
'Evk' posted his/her answer a few minutes before I was about to post this, so I have not evaluated Evk's answer.
After finding this question+answer which might have worked fine but I didn't test it, I stumbled across Michael Ganss's Glob.cs NuGet package, and the results are very nice:
// Requires Glob.cs, (c) 2013 Michael Ganss, downloaded via the NuGet package manager:
// https://www.nuget.org/packages/Glob.cs
// (In Visual Studio, go to Tools->NuGet Package Manager->Package Manager Console.)
// PM> Install-Package Glob.cs -Version 1.3.0
using Glob;
namespace StackOverflow_cs
{
class Program
{
static void Main(string[] args)
{
List<string> directories = new List<string>();
foreach (string arg in args)
{
var dirs = Glob.Glob.Expand(arg, true, true);
foreach (var dir in dirs)
{
directories.Add(dir.FullName);
}
}
Console.WriteLine("Full list of directories specified by the command line args:");
foreach (string dir in directories)
{
Console.WriteLine(" " + dir);
}
// Now go do what I want to do for each of these directories......
}
}
}
But I don't know why I have to say "Glob.Glob.Expand()" instead of simply "Glob.Expand()". Anyway, it works beautifully.
This question already has answers here:
Access to the path is denied when saving image
(26 answers)
Closed 5 years ago.
I'm trying to read a text file with File.ReadAllText and FileStream, but for some reason I get the System.UnauthorizedAccessException every time.
class consultas
{
public consultas()
{
}
private string Inativos = #"C:\Users\Mathias Cruz\Desktop\helloWorld\helloWorld\Consultas";
public string getInativos()
{
try
{
// string path = Directory.GetCurrentDirectory();
this.Inativos = File.ReadAllText(this.Inativos);
}
catch(Exception e)
{
throw e;
}
return this.Inativos;
}
}
Why? I have permissions in that folder, so why do I get this exception?
Based on your code, you are either trying to read a Folder since you didn't specify a extension on your File Path here:
private string Inativos = #"C:\Users\Mathias Cruz\Desktop\helloWorld\helloWorld\Consultas";
It will definitely throw a UnauthorizedAccessException error. So make sure you have the exact file path together with its extension.
Because the path is a directory.
Please check your file address.
This method needs a file address.
Here is a sample code:
File.ReadAllText("C:\\yourfile.txt");
When i use OpenFileDialog to Open file, of course i need to get the file directory and its name to load the file.(to load xml, to access the file i need full path.)
opd is OpenFileDialog
if (opd.ShowDialog() == true)
{
var names = opd.FileNames;
foreach (string name in names)
{
LoadFile(Path.Combine(Path.GetDirectoryName(name), name));
}
}
my question is How Path.GetDirectoryName take the path of the File by Just taking the string ?
Path.GetDirectoryName(name)
name is Just string and this method takes its directory by just taking string? . there can be thousands of files with same name inside computer.
ShortQuestion:
where is opd refrenced?
Edit:
i thought opd.FileNames just takes name of the files.(because of methods name)
and Also i found something interesting.
LoadFile(Path.Combine(Path.GetDirectoryName(name), name));
this works fine Because Path.Combine will just skip the same part of string.
Ex:
string name = #"C:\Users\Default\xml.xml";
string getDirNameResault= Path.GetDirectoryName(name);// this will be C:\Users\Default
So Path.Combine will be
Path.Combine(#"C:\Users\Default", #"C:\Users\Default\xml.xml)
witch returns "C:\Users\Default\xml.xml" !
Path.GetDirectoryName splits the string you already have (from opd) by slash / or \ and then returns everything except last part.
Complete source code of the function in .NET Core foundational libraries (called CoreFX) you can find here: https://github.com/dotnet/corefx/blob/41e203011152581a6c65bb81ac44ec037140c1bb/src/System.Runtime.Extensions/src/System/IO/Path.cs#L151
Code of the implementation:
// Returns the directory path of a file path. This method effectively
// removes the last element of the given file path, i.e. it returns a
// string consisting of all characters up to but not including the last
// backslash ("\") in the file path. The returned value is null if the file
// path is null or if the file path denotes a root (such as "\", "C:", or
// "\\server\share").
//
public static String GetDirectoryName(String path)
{
if (path != null)
{
CheckInvalidPathChars(path);
#if FEATURE_LEGACYNETCF
if (!CompatibilitySwitches.IsAppEarlierThanWindowsPhone8)
{
#endif
string normalizedPath = NormalizePath(path, false);
// If there are no permissions for PathDiscovery to this path, we should NOT expand the short paths
// as this would leak information about paths to which the user would not have access to.
if (path.Length > 0)
{
try
{
// If we were passed in a path with \\?\ we need to remove it as FileIOPermission does not like it.
string tempPath = Path.RemoveLongPathPrefix(path);
// FileIOPermission cannot handle paths that contain ? or *
// So we only pass to FileIOPermission the text up to them.
int pos = 0;
while (pos < tempPath.Length && (tempPath[pos] != '?' && tempPath[pos] != '*'))
pos++;
// GetFullPath will Demand that we have the PathDiscovery FileIOPermission and thus throw
// SecurityException if we don't.
// While we don't use the result of this call we are using it as a consistent way of
// doing the security checks.
if (pos > 0)
Path.GetFullPath(tempPath.Substring(0, pos));
}
catch (SecurityException)
{
// If the user did not have permissions to the path, make sure that we don't leak expanded short paths
// Only re-normalize if the original path had a ~ in it.
if (path.IndexOf("~", StringComparison.Ordinal) != -1)
{
normalizedPath = NormalizePath(path, /*fullCheck*/ false, /*expandShortPaths*/ false);
}
}
catch (PathTooLongException) { }
catch (NotSupportedException) { } // Security can throw this on "c:\foo:"
catch (IOException) { }
catch (ArgumentException) { } // The normalizePath with fullCheck will throw this for file: and http:
}
path = normalizedPath;
#if FEATURE_LEGACYNETCF
}
#endif
int root = GetRootLength(path);
int i = path.Length;
if (i > root)
{
i = path.Length;
if (i == root) return null;
while (i > root && path[--i] != DirectorySeparatorChar && path[i] != AltDirectorySeparatorChar) ;
String dir = path.Substring(0, i);
#if FEATURE_LEGACYNETCF
if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8)
{
if (dir.Length >= MAX_PATH - 1)
throw new PathTooLongException(Environment.GetResourceString("IO.PathTooLong"));
}
#endif
return dir;
}
}
return null;
}
For the complete source code of the function (in Mono) see here: https://github.com/mono/mono/blob/master/mcs/class/corlib/System.IO/Path.cs#L199
name is Just string and this method takes its directory by just taking string? . there can be thousands of files with same name inside computer.
name contains the full path, Path.GetDirectoryName() just strips everything after the last directory separator, Path.Combine(Path.GetDirectoryName(name), name) will not do anything useful:
If path2 includes a root, path2 is returned.
Just use name directly.
This question already has answers here:
See if file path is inside a directory
(2 answers)
Closed 9 years ago.
How can I check in C# if the specific path is to directory in "Program Files" ?
C:\Program Files\someDir... -> is in Program Files
D:\Apps\someDir... -> isn't in Program Files
Thanks!
You can check a path in ProgramFiles(x86) by using the code below:
string path = "yourpath";
var programfileX86 = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86);
if (path.IndexOf(programfileX86, StringComparison.OrdinalIgnoreCase) >= 0)
{
//Found path
}
There're some interseting and subtle issues with the problem:
You should compare paths case insenstive, e.g. "C:\PRogRAM FILES (x86)\Sample" is OK
Separators could be either / or \ so "C:/PRogRAM FILES (x86)/Sample" is OK as well
You should break on separatos only, e.g. "C:\Program Files (x86)MyData\Sample" is not OK
The Code:
public static Boolean PathIncludes(String path, String pathToInclude) {
if (String.IsNullOrEmpty(pathToInclude))
return false;
else if (String.IsNullOrEmpty(path))
return false;
String[] parts = Path.GetFullPath(path).Split(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar, Path.VolumeSeparatorChar);
String[] partsToInclude = Path.GetFullPath(pathToInclude).Split(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar, Path.VolumeSeparatorChar);
if (parts.Length < partsToInclude.Length)
return false;
for (int i = 0; i < partsToInclude.Length; ++i)
if (!String.Equals(parts[i], partsToInclude[i], StringComparison.OrdinalIgnoreCase))
return false;
return true;
}
public static Boolean InProgramFiles(String path) {
return PathIncludes(path, Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86)));
}
// Tests:
// Supposing that ProgramFilesX86 is "C:\Program Files (x86)"
InProgramFiles(#"C:\PRogRAM FILES (x86)\Sample"); // <- true
InProgramFiles(#"C:/PRogRAM FILES (x86)/Sample"); // <- true
InProgramFiles(#"D:/PRogRAM FILES (x86)/Sample"); // <- false
InProgramFiles(#"C:/PRogRAM FILES (x86)A/Sample"); // <- false
First you need to get the program files path. You can do that with System.Environment:
var programFilesPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.ProgramFiles);
If you want the 32 bit program files path you would just change the special folder you are looking for (System.Environment.SpecialFolder.ProgramFilesX86). Then I would do a contains:
var isInProgramFiles = myPath.ToLower().Contains(programFilesPath.ToLower());
That should get you 90% of the way there at least! Best of luck!
EDIT / Sanitize Note
As a side note - there are situations where you can have a valid input and this still wouldn't match. For example - using "/" instead of "\". If you want to make sure you handle these boundary cases correctly, you can create a "DirectoryInfo" object from your input string, validate that it is actually a folder and also standardize the formatting for it. That code looks something like:
if (!System.IO.Directory.Exists(inputPath)) return false;
var checkPath = (new System.IO.DirectoryInfo(inputPath)).FullName;
In this example "inputPath" is the same as "myPath" was above. That should do a moderately good job of sanitizing the input. Best of luck!
If you have a path variable:
string path = "/* whatever path */";
You can check if it is in a folder subfolder this way:
path.IndexOf('\\' + subfolder + '\\') != -1
Note that in more complex cases .. may revert you out of a subdirectory, meaning that you are not in folder f2 if you have something like this:
"\\base_on_drive\\subfolder\\f1\\f2\\..\\a_file.txt"
The .. will bump you back into it's parent folder f1.
if (path.Contains(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles)) || (path.Contains(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86)))
{
}
Assuming your program might be running inside of ProgramFiles, you will probably want to get the fullpath of any path you're checking (in case you get a relative path). In addition, C# has a handy SpecialFolder enumeration that you can use to get the ProgramFiles directory.
The following code will take in a path, convert it to a fullpath, and check if the ProgramFiles directory can be found inside of it. You may want to add some error handling (such as checking for null paths).
static string programfileX86 = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86);
public bool IsInsideProgramFiles(string path)
{
// Get the fullpath in case 'path' is a relative path
string fullPath = System.IO.Path.GetFullPath(path);
return (fullPath.IndexOf(programfileX86, StringComparison.OrdinalIgnoreCase) >= 0);
}
Note: Depending on the systems your code is running in, you may want to check for both SpecialFolder.ProgramFiles and SpecialFolder.ProgramFilesx86.
Credit goes to Toan Nguyen's for the code to get the ProgramFiles directory:
i am trying to use the various file functions in C# like File.GetLastWriteTime, copy command on the file placed at the path greater than maximum allowed path on windows 7 i.e 260. Its giving me an error on long path name. On MSDN support i they have asked to use the \\?\ before the path. I did the same but still i got the same error, it seems it doesn't make any change. Below is my code. Please let me know if i am using it correct or i need to add any thing:
These all lib i am using as the code is having other things also:
the below is the respective code:
filesToBeCopied = Directory.GetFiles(path,"*",SearchOption.AllDirectories);
for (int j = 0; j < filesToBeCopied.Length; j++)
{
try
{
String filepath = #"\\?\" + filesToBeCopied[j];
File.GetLastWriteTime(filepath);
}
catch (Exception ex)
{
MessageBox.Show("Error Inside the single file iteration for the path:" +
filesToBeCopied[j] + " . The exception is :" + ex.Message);
}
}
where as path is the path to the folder at windows machine starting with drive letter. for ex.: d:\abc\bcd\cd\cdc\dc\..........
Here's a solution for at least the copying portion of your request (thank you pinvoke.net):
[DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
static extern bool CopyFile(string lpExistingFileName, string lpNewFileName, bool bFailIfExists);
And then to actually copy your file:
// Don't forget the '\\?\' for long paths
string reallyLongPath = #"\\?\d:\abc\bcd\cd\cdc\dc\..........";
string destination = #"C:\some\other\path\filename.txt";
CopyFile(reallyLongPath , destination, false);
As far as I know, you can't access a file directly if its path is too long (by directly, I mean using the methods of File, by creating a FileInfo via the constructor, or by using Directory.GetFiles(string fileName).
The only way I've found that will let you access such a file is to access a directory somewhere in the path before it gets too long, and then programatically walk down the tree until you get to your file, as seen here.
I've taken my code from there and modified it a little to return a FileInfo object for a file with a path that is "too long". Using this code, you can access the necessary properties on the returned FileInfo object (like LastWriteTime). It still has some limitations though, like the inability to use functions like CopyTo() or OpenText().
// Only call GetFileWithLongPath() if the path is too long
// ... otherwise, new FileInfo() is sufficient
private static FileInfo GetFile(string path)
{
if (path.Length >= MAX_FILE_PATH)
{
return GetFileWithLongPath(path);
}
else return new FileInfo(path);
}
static int MAX_FILE_PATH = 260;
static int MAX_DIR_PATH = 248;
private static FileInfo GetFileWithLongPath(string path)
{
string[] subpaths = path.Split('\\');
StringBuilder sbNewPath = new StringBuilder(subpaths[0]);
// Build longest sub-path that is less than MAX_PATH characters
for (int i = 1; i < subpaths.Length; i++)
{
if (sbNewPath.Length + subpaths[i].Length >= MAX_DIR_PATH)
{
subpaths = subpaths.Skip(i).ToArray();
break;
}
sbNewPath.Append("\\" + subpaths[i]);
}
DirectoryInfo dir = new DirectoryInfo(sbNewPath.ToString());
bool foundMatch = dir.Exists;
if (foundMatch)
{
// Make sure that all of the subdirectories in our path exist.
// Skip the last entry in subpaths, since it is our filename.
// If we try to specify the path in dir.GetDirectories(),
// We get a max path length error.
int i = 0;
while (i < subpaths.Length - 1 && foundMatch)
{
foundMatch = false;
foreach (DirectoryInfo subDir in dir.GetDirectories())
{
if (subDir.Name == subpaths[i])
{
// Move on to the next subDirectory
dir = subDir;
foundMatch = true;
break;
}
}
i++;
}
if (foundMatch)
{
// Now that we've gone through all of the subpaths, see if our file exists.
// Once again, If we try to specify the path in dir.GetFiles(),
// we get a max path length error.
foreach (FileInfo fi in dir.GetFiles())
{
if (fi.Name == subpaths[subpaths.Length - 1])
{
return fi;
}
}
}
}
// If we didn't find a match, return null;
return null;
}
Now that you've seen that, go rinse your eyes and shorten your paths.
try with this code
var path = Path.Combine(#"\\?\", filesToBeCopied[j]); //don't forget extension
"\?\" prefix to a path string tells the Windows APIs to disable all string parsing and to send the string that follows it straight to the file system.
Important : Not all file I/O APIs support "\?\", you should look at the reference topic for each API
http://www.codinghorror.com/blog/2006/11/filesystem-paths-how-long-is-too-long.html
I recently imported some source code for a customer that exceeded the maximum path limit of 256 characters.
The path you pasted was 285 characters long.
As you noted in your comment, MSDN's link here (http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29.aspx#maximum%5Fpath%5Flength) explains this length in greater detail:
In the Windows API (with some exceptions discussed in the following paragraphs), the maximum length for a path is MAX_PATH, which is defined as 260 characters. A local path is structured in the following order: drive letter, colon, backslash, name components separated by backslashes, and a terminating null character. For example, the maximum path on drive D is "D:\some 256-character path string" where "" represents the invisible terminating null character for the current system codepage. (The characters < > are used here for visual clarity and cannot be part of a valid path string.)
With respect to the \\?\ functionality:
Many but not all file I/O APIs support "\?\"; you should look at the reference topic for each API to be sure.