`FileNotFoundException` for network-shared files that do exist. What am I missing?

Question

I need to get a default file icon from shared file. I faced some problems with this and found the question "How to get the associated icon from a network share file".

But now I have another problem with shared files, it looks as if they did not exist. Here is my code:

public static Icon ExtractAssociatedIcon(String filePath)
{
    int index = 0;

    Uri uri;
    if (filePath == null)
    {
        throw new ArgumentException(String.Format("'{0}' is not valid for '{1}'", "null", "filePath"), "filePath");
    }
    try
    {
        uri = new Uri(filePath);
    }
    catch (UriFormatException)
    {
        filePath = Path.GetFullPath(filePath);
        uri = new Uri(filePath);
    }
    if (uri.IsFile)
    {
        if (!File.Exists(filePath))
        {
            throw new FileNotFoundException(filePath);
        }

        StringBuilder iconPath = new StringBuilder(260);
        iconPath.Append(filePath);

        IntPtr handle = SafeNativeMethods.ExtractAssociatedIcon(new HandleRef(null, IntPtr.Zero), iconPath, ref index);
        if (handle != IntPtr.Zero)
        {
            return Icon.FromHandle(handle);
        }
    }
    return null;
}

I always get FileNotFoundException and I don't now why. filePath is OK, and I can access these files through the Explorer. I tried to create FileInfo instance from filePath (I read somewhere that it may help) but still nothing.

What I'm missing?

you should have access to Network location as well as your file path should be something like this: `\\ServerName\FolderName\FileName.txt` and in C# `@"\\ServerName\FolderName\FileName.txt"` — Dgan, Jun 14 '15 at 14:33
Possible duplicate of http://stackoverflow.com/questions/17472168/check-if-directory-exists-on-network-drive (even though the present question is about `File.Exists` and the older question is about `Directory.Exists`). — stakx - no longer contributing, Jun 14 '15 at 14:34
I'm going to guess that your running in a process like IIS and that runs with privileges that don't have access to network resources. — kenny, Jun 14 '15 at 14:52

score 2 · Accepted Answer · edited May 23 '17 at 12:10

IIRC, File.Exists and Directory.Exists have some problems resolving drive letters that are mapped to a network share. They might simply not see these drives, so they report false even though the path points to a valid file.

If you use UNC paths (\\server\share\file.name) instead of drive letters, it might work, so resolve a drive-letter-bassed file path to a UNC path first and pass the latter to File.Exists. See e.g. this answer to that question for an example how to do this.

`FileNotFoundException` for network-shared files that do exist. What am I missing?

1 Answers1