title: How to check if the entered filename contains invalid characters or not
body: <p>How do I check whether the filename entered in a textbox is valid or not?</p>
  
  <p>In a text box I am entering or selecting the path and filename from local machine or remote machine, once I selected the filename then I want to check if the entered file name is has any invalid charcaters.
  I cannot give like textbox = “Selected Path”, because I can select a file from local machine or remote machine but the file name is same.</p>