Best Way to Resolve File Path Too Long Exception

Best way to resolve file path too long exception

As the cause of the error is obvious, here's some information that should help you solve the problem:

See this MS article about Naming Files, Paths, and Namespaces

Here's a quote from the link:

Maximum Path Length Limitation 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<NUL>" where "<NUL>" 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.)

And a few workarounds (taken from the comments):

There are ways to solve the various problems. The basic idea of the solutions listed below is always the same: Reduce the path-length in order to have path-length + name-length < MAX_PATH. You may:

• Share a subfolder
• Use the commandline to assign a drive letter by means of SUBST
• Use AddConnection under VB to assign a drive letter to a path

Best way to resolve file path too long exception

As the cause of the error is obvious, here's some information that should help you solve the problem:

See this MS article about Naming Files, Paths, and Namespaces

Here's a quote from the link:

Maximum Path Length Limitation 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<NUL>" where "<NUL>" 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.)

And a few workarounds (taken from the comments):

There are ways to solve the various problems. The basic idea of the solutions listed below is always the same: Reduce the path-length in order to have path-length + name-length < MAX_PATH. You may:

• Share a subfolder
• Use the commandline to assign a drive letter by means of SUBST
• Use AddConnection under VB to assign a drive letter to a path

The specified path, file name, or both are too long

If you are not reading a file, you do not need to use the System.IO.File class. It appears that you are just trying to get a byte array of a string. You need to use an Encoding class such as System.Text.Encoding

var bts = System.Text.Encoding.ASCII.GetBytes(filename.ToCharArray());

How to avoid System.IO.PathTooLongException?

As described in Jeremy Kuhne's blog, .NET Framework 4.6.2 removes the MAX_PATH limitation where possible, without breaking backwards compatibility.

Why do I still have a DirectoryNotFoundException because of Path Too Long under .NET 4.7.2?

Maybe I'm reading that sentence incorrectly,

The absence of targeting the .NET Framework 4.6.2 or setting the AppContext switch results in the existing behavior of being blocked from using paths longer than MAXPATH. The behavior is opt-in to maintain backwards compatibility for existing applications.

but it seemed to me that the simple fact of targeting .NET 4.7.2 would result in the behavior of allowing paths longer than MAXPATH.

Nevertherless, I had to manually enable it in the app.manifest

<application xmlns="urn:schemas-microsoft-com:asm.v3">
    <windowsSettings>
      <longPathAware xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">true</longPathAware>
    </windowsSettings>
  </application>

The code doesn't trigger any exception anymore.

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