Private Function OpenFile() As FileStream

        ' Displays an OpenFileDialog and shows the read/only files.

        Dim DlgOpenFile As New OpenFileDialog()
        DlgOpenFile.ShowReadOnly = True

        If DlgOpenFile.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
            Dim path As New String("")

            ' If ReadOnlyChecked is true, uses the OpenFile method to
            ' open the file with read/only access.
            Try
                If (DlgOpenFile.ReadOnlyChecked = True) Then
                    Return DlgOpenFile.OpenFile()
                Else
                    ' Otherwise, opens the file with read/write access.
                    Path = DlgOpenFile.FileName
                    Return New FileStream(Path, System.IO.FileMode.Open, _
                            System.IO.FileAccess.ReadWrite)
                End If
            Catch SecEx As SecurityException
                ' The user lacks appropriate permissions to read files, discover paths, etc.
                MessageBox.Show("Security error. Please contact your administrator for details.\n\n" & _
                    "Error message: " & SecEx.Message * "\n\n" & _
                    "Details (send to Support):\n\n" & SecEx.StackTrace)
            Catch Ex As Exception
                ' Could not load the image - probably related to Windows file system permissions.
                MessageBox.Show("Cannot display the image: " & path.Substring(path.LastIndexOf("\\")) & _
                         ". You may not have permission to read the file, or " & _
                        "it may be corrupt.\n\nReported error: " + ex.Message)
            End Try
        End If

        Return Nothing
    End Function

    private FileStream OpenFile()
    {
        // Displays an OpenFileDialog and shows the read/only files.

        OpenFileDialog dlgOpenFile = new OpenFileDialog();
        dlgOpenFile.ShowReadOnly = true;


        if(dlgOpenFile.ShowDialog() == DialogResult.OK)
        {

            // If ReadOnlyChecked is true, uses the OpenFile method to
            // open the file with read/only access.
            string path = null;

            try {
                if(dlgOpenFile.ReadOnlyChecked == true)
                {
                    return (FileStream)dlgOpenFile.OpenFile();
                }

                // Otherwise, opens the file with read/write access.
                else
                {
                    path = dlgOpenFile.FileName;
                    return new FileStream(path, System.IO.FileMode.Open,
                                System.IO.FileAccess.ReadWrite);
                }
            } catch (SecurityException ex)
                {
                    // The user lacks appropriate permissions to read files, discover paths, etc.
                    MessageBox.Show("Security error. Please contact your administrator for details.\n\n" +
                        "Error message: " + ex.Message + "\n\n" +
                        "Details (send to Support):\n\n" + ex.StackTrace
                    );
                }
                catch (Exception ex)
                {
                    // Could not load the image - probably related to Windows file system permissions.
                    MessageBox.Show("Cannot display the image: " + path.Substring(path.LastIndexOf('\\'))
                        + ". You may not have permission to read the file, or " +
                        "it may be corrupt.\n\nReported error: " + ex.Message);
                }
        }

        return null;
    }

private:
   FileStream^ OpenFile()
   {
      // Displays an OpenFileDialog and shows the read/only files.
      OpenFileDialog^ dlgOpenFile = gcnew OpenFileDialog;
      dlgOpenFile->ShowReadOnly = true;
      if ( dlgOpenFile->ShowDialog() == ::DialogResult::OK )
      {
         // If ReadOnlyChecked is true, uses the OpenFile method to
         // open the file with read/only access.
         if ( dlgOpenFile->ReadOnlyChecked == true )
         {
            return dynamic_cast<FileStream^>(dlgOpenFile->OpenFile());
         }
         // Otherwise, opens the file with read/write access.
         else
         {
            String^ path = dlgOpenFile->FileName;
            return gcnew FileStream( path,System::IO::FileMode::Open,System::IO::FileAccess::ReadWrite );
         }
      }

      return nullptr;
   }