Is there any universal way in .net or win api to check if file / folder name is not special reserved one like "COM0", "LPT1" and etc?

Question

Aside of doing crazy cycles like this for every type of port:

bool IsGoodFileName(string file_name)
{
   for (int i = 0; i < 256; i++)
      if (string.Compare(file_name, "COM" + i) == 0)
         return false;

   return true;
}

Answer 1

According to the documentation, you don't have to check beyond port 9 for these, so you could do something like this:

static bool IsGoodFileName(string file_name)
{
    var reserved = new[]
        {
            "CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9",
            "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9"
        };
    var fileName = Path.GetFileNameWithoutExtension(file_name);
    //TODO: handle case where fileName is null.
    return !reserved.Any(r => fileName.Equals(r, StringComparison.InvariantCultureIgnoreCase));
}

And indeed, Windows Explorer lets you make a file named COM20, so I don't think you need to check those.