How to open hidden file using C#?

To open a hidden file, first make it visible. You can do this by removing the hidden attribute set on it −

FileInfo file= new FileInfo(Environment.CurrentDirectory + @"\myFile.txt");
file.Attributes &= ~FileAttributes.Hidden;

Now treat it as a normal text file and open it. Read the content −

using (StreamReader sr = new StreamReader("myFile.txt")) {
   string line;

   while ((line = sr.ReadLine()) != null) {
      Console.WriteLine(line);
   }
}

After reading, set the attribute as hidden again to hide the file −

file.Attributes |= FileAttributes.Hidden;