private void AddBookmarkButton_Click(object sender, RoutedEventArgs e)
 {
     if (String.IsNullOrWhiteSpace(AddBookmarkName.Text))
     {
         MessageBox.Show("Name cannot be empty.", "Info : Error while adding bookmark",
                         MessageBoxButton.OK,
                         MessageBoxImage.Information);
         return;
     }
     foreach (Bookmark bookmark in bookmarks.allBookmarks.Values)
     {
         if (bookmark.Name == AddBookmarkName.Text)
         {
             MessageBox.Show("Bookmark already exists.",
                             "Info : Error while adding bookmark",
                             MessageBoxButton.OK,
                             MessageBoxImage.Information);
             return;
         }
         if (bookmark.Url == AddBookmarkUrl.Text)
         {
             MessageBox.Show("Bookmark with this url already exist : " + bookmark.Name,
                             "Info : Error while adding bookmark",
                             MessageBoxButton.OK,
                             MessageBoxImage.Information);
             return;
         }
     }
     if (!IsValidUrl(AddBookmarkUrl.Text))
     {
         MessageBox.Show("Url cannot be empty and must begin with \"http://\", \"https://\" or \"ftp://\".",
                         "Info : Error while adding bookmark",
                         MessageBoxButton.OK,
                         MessageBoxImage.Information);
         return;
     }
     bookmarks.allBookmarks[AddBookmarkName.Text] = bookmarks.BuildBoomark(
         AddBookmarkName.Text,
         AddBookmarkUrl.Text,
         (bool)AddBookmarkIe.IsChecked,
         (bool)AddBookmarkChrome.IsChecked,
         (bool)AddBookmarkFirefox.IsChecked);
     UIInsertBookmark(bookmarks.allBookmarks[AddBookmarkName.Text]);
     bookmarksModified = true;
 }