private void pdfButton_Click(object sender, RoutedEventArgs e)
{
System.Windows.Forms.SaveFileDialog fileDialog = new System.Windows.Forms.SaveFileDialog();
fileDialog.Title = "Specify output pdf file";
fileDialog.Filter = "pdf file|*.pdf";
fileDialog.RestoreDirectory = true;
fileDialog.FileName = outputPdfPath;
if (fileDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
outputPdfPath = fileDialog.FileName;
checkPlayButton();
}
}