// Fig 19.5: FileTestForm.cs
// Using classes File and Directory.
using System;
using System.Windows.Forms;
using System.IO;

namespace FileTest
{
   // displays contents of files and directories
   public partial class FileTestForm : Form
   {
      // parameterless constructor
      public FileTestForm()
      {
         InitializeComponent();
      } // end constructor

      // invoked when user presses key
      private void inputTextBox_KeyDown( object sender, KeyEventArgs e )
      {
         // determine whether user pressed Enter key
         if ( e.KeyCode == Keys.Enter )
         {
            // get user-specified file or directory
             string fileName = inputTextBox.Text;

            // determine whether fileName is a file
            if ( File.Exists(fileName) )
            {
               // get file's creation date, modification date, etc.               
               GetInformation( fileName );

               // display file contents through StreamReader
               try
               {
                   // obtain reader and file contents
                   using (StreamReader reader = new StreamReader(fileName))
                   {
                       outputTextBox.AppendText(reader.ReadToEnd());
                   }

               } // end try
               catch ( IOException )
               {
                  MessageBox.Show( "Error reading from file",
                                   "File Error", MessageBoxButtons.OK,
                                   MessageBoxIcon.Error );
               } // end catch
            } // end if
            // determine whether fileName is a directory
            else if ( Directory.Exists(fileName) )
            {
               // get directory's creation date, 
               // modification date, etc.
               GetInformation( fileName );

               // obtain file/directory list of specified directory
               string[] directoryList;
               directoryList = Directory.GetDirectories(fileName);

               outputTextBox.AppendText("Directory contents: " + Environment.NewLine);

               // output directoryList contents
               foreach (var directory in directoryList)
               {
                   outputTextBox.AppendText(directory + Environment.NewLine);
               }

               // obtain file/directory list of specified directory
               string[] fileList;
               fileList = Directory.GetFiles(fileName);

               outputTextBox.AppendText("File list: " + Environment.NewLine);

               // output directoryList contents
               foreach (var file in fileList)
               {
                   outputTextBox.AppendText(file + Environment.NewLine);
               }
            } // end else if
            else
            {
               // notify user that neither file nor directory exists
               MessageBox.Show( inputTextBox.Text +
                                " does not exist", "File Error",
                                MessageBoxButtons.OK, MessageBoxIcon.Error );
            } // end else
         } // end if
      } // end method inputTextBox_KeyDown

      // get information on file or directory,
      // and output it to outputTextBox
      private void GetInformation( string fileName )
      {
         outputTextBox.Clear();

         // output that file or directory exists
         outputTextBox.AppendText(fileName + " exists" 
                                   + Environment.NewLine);

         // output when file or directory was created
         outputTextBox.AppendText( "Created: " +
                                   File.GetCreationTime(fileName) 
                                   + Environment.NewLine);

         // output when file or directory was last modified
         outputTextBox.AppendText( "Last modified: " +
                                   File.GetLastWriteTime(fileName)
                                   + Environment.NewLine);

         // output when file or directory was last accessed
         outputTextBox.AppendText( "Last accessed: " +
                                   File.GetLastAccessTime(fileName)
                                   + Environment.NewLine);
      } // end method GetInformation
   } // end class FileTestForm
} // end namespace FileTest