Remove invalid (disallowed, bad) characters from FileName (or Directory, Folder, File) [duplicate]

Answer 1

I know this is a few years old but here is another solution for reference.

public string GetSafeFilename(string filename)
{

    return string.Join("_", filename.Split(Path.GetInvalidFileNameChars()));

}

Answer 2

A different approach that is compatible with .NET 4. See my comments above explaining the need.

public static string ScrubFileName(string value)
{
   var sb = new StringBuilder(value);
   foreach (char item in Path.GetInvalidFileNameChars())
   {
      sb.Replace(item.ToString(), "");
   }
   return sb.ToString();
}

Answer 3

Try the following

public string MakeValidFileName(string name) {
  var builder = new StringBuilder();
  var invalid = System.IO.Path.GetInvalidFileNameChars();
  foreach ( var cur in name ) {
    if ( !invalid.Contains(cur) ) {
      builder.Append(cur);
    }
  }
  return builder.ToString();
}

Answer 4

If you look for "concise" when you say simple:

public string StripInvalidChars(string filename) {
  return new String(
    filename.Except(System.IO.Path.GetInvalidFileNameChars()).ToArray()
  );
}

That said, I'd go with JaredPar's solution. It's probably easier to read (depending on taste, background), my gut feeling is that it is more efficient (although I'm not sure how efficient you have to be stripping that dozen of invalid chars from a limited length filename) and his use of a StringBuilder() seems to fit perfectly to your example.