How Path.GetDirectoryName Works? - c#

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.

Related

C# FolderBrowserDialog - how to include shared folders

I create a FolderBrowserDialog as follows (only an excerpt -not complete code):
string tempSetWorkingPath = null;
try
{
FolderBrowserDialog folderDlg = new System.Windows.Forms.FolderBrowserDialog();
folderDlg.ShowNewFolderButton = true;
folderDlg.Description = "Selected your working folder. This is where your PDF files will be saved.";
folderDlg.RootFolder = Environment.SpecialFolder.MyComputer;
folderDlg.SelectedPath = (Convert.ToString(WorkingPath).Trim().Length == 0) ? ((int)Environment.SpecialFolder.MyComputer).ToString() : WorkingPath;
if (folderDlg.ShowDialog() == DialogResult.OK)
{
tempSetWorkingPath = folderDlg.SelectedPath;
}
else
{
tempSetWorkingPath = "";
}
}
...
The code works well, except the only folders that are showing are the local folders. Users have DropBox and OneDrive shared folders on their systems and to select one of those directories, the user needs to cycle through the windows user directories and select the folder from there. On some systems I have seen over the last few months, I've seen the DropBox and OneDrive directories appear below the DeskTop directory ... but I have not, despite hours of searching - found a way to achive that.
How can I achieve that?
MTIA
DWE
Given I have observed a large number of queries posted here and elsewhere regarding the inclusion of the directories, including shared directories and given the response by # Mailosz, it seems that the root folder property of the folder dialog holds the key - it Gets or sets the root folder where the browsing starts from and thats what my code was missing.
The full code to the function referred to in my question appears below, in the event it assists someone else.
/// <summary>
/// presents the user with a folder dialog
/// Returns a full qualified directory chosen by the user
/// </summary>
/// <param name="WorkingPath">if a fully qualified directory name is provided, then the folder structure in the folder dialog will open to the directory selected</param>
/// <returns>Returns a full qualified directory chosen by the user or if no directory was chosen, an empty string</returns>
public string SetWorkingPath(string WorkingPath)
{
string tempSetWorkingPath = null;
try
{
FolderBrowserDialog folderDlg = new System.Windows.Forms.FolderBrowserDialog();
// check our proposed working path and if its valid
if((!string.IsNullOrEmpty(WorkingPath) && (WorkingPath != null)))
{
if (!Directory.Exists(WorkingPath))
WorkingPath = string.Empty;
}
else // if we are empty or null set us to empty
{
WorkingPath = string.Empty;
}
folderDlg.ShowNewFolderButton = true;
folderDlg.Description = "Please select your working folder. This is where your PDF files will be saved.";
folderDlg.RootFolder = Environment.SpecialFolder.Desktop;//.MyComputer;
folderDlg.SelectedPath = (Convert.ToString(WorkingPath).Trim().Length == 0) ? ((int)Environment.SpecialFolder.MyComputer).ToString() : WorkingPath;
if (folderDlg.ShowDialog() == DialogResult.OK)
{
// make sure we have a backslash on the end of our directory string
tempSetWorkingPath = PathAddBackslash(folderDlg.SelectedPath);
}
else
{
// return an empty string
tempSetWorkingPath = string.Empty;
}
}
catch (Exception ex)
{
tempSetWorkingPath = string.Empty;
throw (ex);
}
return tempSetWorkingPath;
}
public string PathAddBackslash(string path)
{
// They're always one character but EndsWith is shorter than
// array style access to last path character. Change this
// if performance are a (measured) issue.
string separator1 = Path.DirectorySeparatorChar.ToString();
string separator2 = Path.AltDirectorySeparatorChar.ToString();
// Trailing white spaces are always ignored but folders may have
// leading spaces. It's unusual but it may happen. If it's an issue
// then just replace TrimEnd() with Trim(). Tnx Paul Groke to point this out.
path = path.TrimEnd();
// Argument is always a directory name then if there is one
// of allowed separators then I have nothing to do.
if (path.EndsWith(separator1) || path.EndsWith(separator2))
return path;
// If there is the "alt" separator then I add a trailing one.
// Note that URI format (file://drive:\path\filename.ext) is
// not supported in most .NET I/O functions then we don't support it
// here too. If you have to then simply revert this check:
// if (path.Contains(separator1))
// return path + separator1;
//
// return path + separator2;
if (path.Contains(separator2))
return path + separator2;
// If there is not an "alt" separator I add a "normal" one.
// It means path may be with normal one or it has not any separator
// (for example if it's just a directory name). In this case I
// default to normal as users expect.
return path + separator1;
}

How to prevent Directory.GetFiles to "check" recycle bin and other "unsafe" places?

So guys, I have a function in my application which to search for certain file in certain directory using GetFiles method
System.IO.Directory.GetFiles(string path, string searchPattern, System.IO.SearchOption)
It works fine, until when I choose drive directory (D:\ or C:\ and such) to be searched, because it's also accessing the Recycle Bin, and then restricted
Access to the path 'D:\$RECYCLE.BIN\S-1-5-21-106145493-3722843178-2978326776-1010' is denied.
It's also need to be able to search subfolders (SearchOption.AllDirectories) too.
How to SKIP such place to be searched? Because there may be any other folder which access also denied.
I capitalize SKIP because if I use try catch and an exception caught, then the entire search will also fail.
Thanks. Please clarify anything you need.
EDITed for more clarity.
When recursively scanning a directory tree, say using a recursive method which takes the directory to start with as a parameter, you can get the attributes of the directory. Then check whether it's a system directory AND NOT a root directory like "C:\" - in that case you want to skip that directory, as it may be, for instance, the recycle bin.
Here's some code that does this, and also catches some common exceptions which occurred when I fiddled with directory scanning.
void scan_dir(string path)
{
// Exclude some directories according to their attributes
string[] files = null;
string skipReason = null;
var dirInfo = new DirectoryInfo( path );
var isroot = dirInfo.Root.FullName.Equals( dirInfo.FullName );
if ( // as root dirs (e.g. "C:\") apparently have the system + hidden flags set, we must check whether it's a root dir, if it is, we do NOT skip it even though those attributes are present
(dirInfo.Attributes.HasFlag( FileAttributes.System ) && !isroot) // We must not access such folders/files, or this crashes with UnauthorizedAccessException on folders like $RECYCLE.BIN
)
{ skipReason = "system file/folder, no access";
}
if ( null == skipReason )
{ try
{ files = Directory.GetFiles( path );
}
catch (UnauthorizedAccessException ex)
{ skipReason = ex.Message;
}
catch (PathTooLongException ex)
{ skipReason = ex.Message;
}
}
if (null != skipReason)
{ // perhaps do some error logging, stating skipReason
return; // we skip this directory
}
foreach (var f in files)
{ var fileAttribs = new FileInfo( f ).Attributes;
// do stuff with file if the attributes are to your liking
}
try
{ var dirs = Directory.GetDirectories( path );
foreach (var d in dirs)
{ scan_dir( d ); // recursive call
}
}
catch (PathTooLongException ex)
{ Trace.WriteLine(ex.Message);
}
}

How to create a path using the Windows.Storage API?

System.IO.CreateDirectory() is not available on .NET for Windows Store Apps.
How can I implement this equivalent method? StorageFolder.CreateFolderAsync() creates a subfolder inside the current folder, but in my case I have a path like and need to create all folders that doesn't exist in this path.
The path is inside the app's sandbox in windows.
There's no API with exactly the same behaviour of System.IO.CreateDirectory(), so I implemented it using Windows.Storage classes:
// Any and all directories specified in path are created, unless they already exist or unless
// some part of path is invalid. If the directory already exists, this method does not create a
// new directory.
// The path parameter specifies a directory path, not a file path, and it must in
// the ApplicationData domain.
// Trailing spaces are removed from the end of the path parameter before creating the directory.
public static void CreateDirectory(string path)
{
path = path.Replace('/', '\\').TrimEnd('\\');
StorageFolder folder = null;
foreach(var f in new StorageFolder[] {
ApplicationData.Current.LocalFolder,
ApplicationData.Current.RoamingFolder,
ApplicationData.Current.TemporaryFolder } )
{
string p = ParsePath(path, f);
if (f != null)
{
path = p;
folder = f;
break;
}
}
if(path == null)
throw new NotSupportedException("This method implementation doesn't support " +
"parameters outside paths accessible by ApplicationData.");
string[] folderNames = path.Split('\\');
for (int i = 0; i < folderNames.Length; i++)
{
var task = folder.CreateFolderAsync(folderNames[i], CreationCollisionOption.OpenIfExists).AsTask();
task.Wait();
if (task.Exception != null)
throw task.Exception;
folder = task.Result;
}
}
private static string ParsePath(string path, StorageFolder folder)
{
if (path.Contains(folder.Path))
{
path = path.Substring(path.LastIndexOf(folder.Path) + folder.Path.Length + 1);
return path;
}
return null;
}
To create folders outside your app's sandbox in windows store app, you'll have to add the document library in app-manifest, along with file permissions.
For a much more detailed explanation regarding library and documents, Refer this blog

Require a Regular Expression to valid FileName? [duplicate]

This question already has answers here:
How do I check if a given string is a legal/valid file name under Windows?
(27 answers)
Closed 7 years ago.
Is there a method in the System.IO namespace that checks the validity of a filename?
For example, C:\foo\bar would validate and :"~-* would not
Or a little trickier, X:\foo\bar would validate is there is an X: drive on the system, but wouldn't otherwise.
I suppose I could write such a method myself, but I'm more interested in a built-in one.
Just do;
System.IO.FileInfo fi = null;
try {
fi = new System.IO.FileInfo(fileName);
}
catch (ArgumentException) { }
catch (System.IO.PathTooLongException) { }
catch (NotSupportedException) { }
if (ReferenceEquals(fi, null)) {
// file name is not valid
} else {
// file name is valid... May check for existence by calling fi.Exists.
}
For creating a FileInfo instance the file does not need to exist.
You can get a list of invalid characters from Path.GetInvalidPathChars and GetInvalidFileNameChars as discussed in this question.
As noted by jberger, there some other characters which are not included in the response from this method. For much more details of the windows platform, take a look at Naming Files, Paths and Namespaces on MSDN.
As Micah points out, there is Directory.GetLogicalDrives to get a list of valid drives.
You could make use the System.Uri class. The Uri class isn't just useful for web URLs, it also handles file system paths as well. Use the Uri.TryCreate method to find if the path is rooted then use the IsLoopback property to determine if the Uri references the local machine.
Here is a simple method which determines if a string is a valid, local, and rooted file path.
public bool IsPathValidRootedLocal(String pathString) {
Uri pathUri;
Boolean isValidUri = Uri.TryCreate(pathString, UriKind.Absolute, out pathUri);
return isValidUri && pathUri != null && pathUri.IsLoopback;
}
I am confident this will work.
There are several methods you could use that exist in the System.IO namespace:
Directory.GetLogicalDrives() // Returns an array of strings like "c:\"
Path.GetInvalidFileNameChars() // Returns an array of characters that cannot be used in a file name
Path.GetInvalidPathChars() // Returns an array of characters that cannot be used in a path.
As suggested you could then do this:
bool IsValidFilename(string testName) {
string regexString = "[" + Regex.Escape(Path.GetInvalidPathChars()) + "]";
Regex containsABadCharacter = new Regex(regexString);
if (containsABadCharacter.IsMatch(testName)) {
return false;
}
// Check for drive
string pathRoot = Path.GetPathRoot(testName);
if (Directory.GetLogicalDrives().Contains(pathRoot)) {
// etc
}
// other checks for UNC, drive-path format, etc
return true;
}
Thought I would post a solution I cobbled together from bits of answers I found after searching for a robust solution to the same problem. Hopefully it helps someone else.
using System;
using System.IO;
//..
public static bool ValidateFilePath(string path, bool RequireDirectory, bool IncludeFileName, bool RequireFileName = false)
{
if (string.IsNullOrEmpty(path)) { return false; }
string root = null;
string directory = null;
string filename = null;
try
{
// throw ArgumentException - The path parameter contains invalid characters, is empty, or contains only white spaces.
root = Path.GetPathRoot(path);
// throw ArgumentException - path contains one or more of the invalid characters defined in GetInvalidPathChars.
// -or- String.Empty was passed to path.
directory = Path.GetDirectoryName(path);
// path contains one or more of the invalid characters defined in GetInvalidPathChars
if (IncludeFileName) { filename = Path.GetFileName(path); }
}
catch (ArgumentException)
{
return false;
}
// null if path is null, or an empty string if path does not contain root directory information
if (String.IsNullOrEmpty(root)) { return false; }
// null if path denotes a root directory or is null. Returns String.Empty if path does not contain directory information
if (String.IsNullOrEmpty(directory)) { return false; }
if (RequireFileName)
{
// if the last character of path is a directory or volume separator character, this method returns String.Empty
if (String.IsNullOrEmpty(filename)) { return false; }
// check for illegal chars in filename
if (filename.IndexOfAny(Path.GetInvalidFileNameChars()) >= 0) { return false; }
}
return true;
}
Even if the filename is valid, you may still want to touch it to be sure the user has permission to write.
If you won't be thrashing the disk with hundreds of files in a short period of time, I think creating an empty file is a reasonable approach.
If you really want something lighter, like just checking for invalid chars, then compare your filename against Path.GetInvalidFileNameChars().
Several of the System.IO.Path methods will throw exceptions if the path or filename is invalid:
Path.IsPathRooted()
Path.GetFileName()
http://msdn.microsoft.com/en-us/library/system.io.path_methods.aspx
I've had luck using regular expressions as others have shown.
One thing to keep in mind is that Windows at least prohibits some filenames that otherwise containlegal characters. A few come to mind: com, nul, prn.
I don't have it with me now, but I have a regex that takes these filename into consideration. If you want I can post it, otherwise I'm sure you can find it the same way I did: Google.
-Jay
Use the static GetInvalidFileNameChars method on the Path class in the System.IO namespace to determine what characters are illegal in a file name.
To do so in a path, call the static GetInvalidPathChars method on the same class.
To determine if the root of a path is valid, you would call the static GetPathRoot method on the Path class to get the root, then use the Directory class to determine if it is valid. Then you can validate the rest of the path normally.
Try out this method which would try to cover for all the possible Exceptions scenarios. It would work for almost all the Windows related Paths.
/// <summary>
/// Validate the Path. If path is relative append the path to the project directory by default.
/// </summary>
/// <param name="path">Path to validate</param>
/// <param name="RelativePath">Relative path</param>
/// <param name="Extension">If want to check for File Path</param>
/// <returns></returns>
private static bool ValidateDllPath(ref string path, string RelativePath = "", string Extension = "") {
// Check if it contains any Invalid Characters.
if (path.IndexOfAny(Path.GetInvalidPathChars()) == -1) {
try {
// If path is relative take %IGXLROOT% as the base directory
if (!Path.IsPathRooted(path)) {
if (string.IsNullOrEmpty(RelativePath)) {
// Exceptions handled by Path.GetFullPath
// ArgumentException path is a zero-length string, contains only white space, or contains one or more of the invalid characters defined in GetInvalidPathChars. -or- The system could not retrieve the absolute path.
//
// SecurityException The caller does not have the required permissions.
//
// ArgumentNullException path is null.
//
// NotSupportedException path contains a colon (":") that is not part of a volume identifier (for example, "c:\").
// PathTooLongException The specified path, file name, or both 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.
// RelativePath is not passed so we would take the project path
path = Path.GetFullPath(RelativePath);
} else {
// Make sure the path is relative to the RelativePath and not our project directory
path = Path.Combine(RelativePath, path);
}
}
// Exceptions from FileInfo Constructor:
// System.ArgumentNullException:
// fileName is null.
//
// System.Security.SecurityException:
// The caller does not have the required permission.
//
// System.ArgumentException:
// The file name is empty, contains only white spaces, or contains invalid characters.
//
// System.IO.PathTooLongException:
// The specified path, file name, or both 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.
//
// System.NotSupportedException:
// fileName contains a colon (:) in the middle of the string.
FileInfo fileInfo = new FileInfo(path);
// Exceptions using FileInfo.Length:
// System.IO.IOException:
// System.IO.FileSystemInfo.Refresh() cannot update the state of the file or
// directory.
//
// System.IO.FileNotFoundException:
// The file does not exist.-or- The Length property is called for a directory.
bool throwEx = fileInfo.Length == -1;
// Exceptions using FileInfo.IsReadOnly:
// System.UnauthorizedAccessException:
// Access to fileName is denied.
// The file described by the current System.IO.FileInfo object is read-only.-or-
// This operation is not supported on the current platform.-or- The caller does
// not have the required permission.
throwEx = fileInfo.IsReadOnly;
if (!string.IsNullOrEmpty(Extension)) {
// Validate the Extension of the file.
if (Path.GetExtension(path).Equals(Extension, StringComparison.InvariantCultureIgnoreCase)) {
// Trim the Library Path
path = path.Trim();
return true;
} else {
return false;
}
} else {
return true;
}
} catch (ArgumentNullException) {
// System.ArgumentNullException:
// fileName is null.
} catch (System.Security.SecurityException) {
// System.Security.SecurityException:
// The caller does not have the required permission.
} catch (ArgumentException) {
// System.ArgumentException:
// The file name is empty, contains only white spaces, or contains invalid characters.
} catch (UnauthorizedAccessException) {
// System.UnauthorizedAccessException:
// Access to fileName is denied.
} catch (PathTooLongException) {
// System.IO.PathTooLongException:
// The specified path, file name, or both 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.
} catch (NotSupportedException) {
// System.NotSupportedException:
// fileName contains a colon (:) in the middle of the string.
} catch (FileNotFoundException) {
// System.FileNotFoundException
// The exception that is thrown when an attempt to access a file that does not
// exist on disk fails.
} catch (IOException) {
// System.IO.IOException:
// An I/O error occurred while opening the file.
} catch (Exception) {
// Unknown Exception. Might be due to wrong case or nulll checks.
}
} else {
// Path contains invalid characters
}
return false;
}
I don't know of anything out of the box that can just validate all of that for you, however the Path class in .NET can help you out tremendously.
For starters, it has:
char[] invalidChars = Path.GetInvalidFileNameChars(); //returns invalid charachters
or:
Path.GetPathRoot(string); // will return the root.
Probably the bast way is to build a custom method mixing a combination of regex and small look up on your file system (to see the drives, for example)
This will get you the drives on the machine:
System.IO.DriveInfo.GetDrives()
These two methods will get you the bad characters to check:
System.IO.Path.GetInvalidFileNameChars();
System.IO.Path.GetInvalidPathChars();
Think it's too late to answer but... :)
in case of path with volume name you could write something like this:
using System;
using System.Linq;
using System.IO;
// ...
var drives = Environment.GetLogicalDrives();
var invalidChars = Regex.Replace(new string(Path.GetInvalidFileNameChars()), "[\\\\/]", "");
var drive = drives.FirstOrDefault(d => filePath.StartsWith(d));
if (drive != null) {
var fileDirPath = filePath.Substring(drive.Length);
if (0 < fileDirPath.Length) {
if (fileDirPath.IndexOfAny(invalidChars.ToCharArray()) == -1) {
if (Path.Combine(drive, fileDirPath) != drive) {
// path correct and we can proceed
}
}
}
}

Error: File Path is Too Long

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.

Categories

Resources