In C check that filename is possibly valid not that it exists

Question

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

User · Answer

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;
}

User · Answer

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     gt   0    return false              return true

User · Answer

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        lt summary gt      Validate the Path  If path is relative append the path to the project directory by default       lt  summary gt       lt param name  path  gt Path to validate lt  param gt       lt param name  RelativePath  gt Relative path lt  param gt       lt param name  Extension  gt If want to check for File Path lt  param gt       lt returns gt  lt  returns gt  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

User · Answer

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   gt  filePath StartsWith d    if  drive    null        var fileDirPath   filePath Substring drive Length       if  0  lt  fileDirPath Length            if  fileDirPath IndexOfAny invalidChars ToCharArray       -1                if  Path Combine drive  fileDirPath     drive                       path correct and we can proceed

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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   gt  filePath StartsWith d    if  drive    null        var fileDirPath   filePath Substring drive Length       if  0  lt  fileDirPath Length            if  fileDirPath IndexOfAny invalidChars ToCharArray       -1                if  Path Combine drive  fileDirPath     drive                       path correct and we can proceed

User · Answer

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

User · Answer

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

User · Answer

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;
}

User · Answer

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;
}

User · Answer

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

User · Answer

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  amp  amp  pathUri    null  amp  amp  pathUri IsLoopback      I am confident this will work

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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  amp  amp  pathUri    null  amp  amp  pathUri IsLoopback      I am confident this will work

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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;
}

User · Answer

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

User · Answer

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     gt   0    return false              return true

User · Answer

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

User · Answer

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

User · Answer

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        lt summary gt      Validate the Path  If path is relative append the path to the project directory by default       lt  summary gt       lt param name  path  gt Path to validate lt  param gt       lt param name  RelativePath  gt Relative path lt  param gt       lt param name  Extension  gt If want to check for File Path lt  param gt       lt returns gt  lt  returns gt  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

User · Answer

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

User · Answer

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

User · Answer

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

[c#] In C# check that filename is possibly valid (not that it exists)

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Examples related to validation

Examples related to file

[c#] In C# check that filename is *possibly* valid (not that it exists)

Examples related to c#

Examples related to validation

Examples related to file

[c#] In C# check that filename is possibly valid (not that it exists)