public async void DublicatedPagesAsync()
{
var dublicated = await _pageManager.DuplicatePageAsync(_groupDao.SourcePages, _groupDao.Group.Count);
int remainded = dublicated.Length % Infrastructure.Common.Properties.GetInstance().Groups;
_groupDao.DublicatedPages = remainded != 0
? await _pageManager.AddEmptyPagesAsync(dublicated, Infrastructure.Common.Properties.GetInstance().Groups - remainded)
: dublicated;
}