private void OnCurrentPageChanged(object sender, EventArgs e)
 {
     //currentPage will changed only throuth IRegistrationCarouselPage
     if (page.CurrentPage.TabIndex > currentPage)
     {
         NextRegistrationPage?.Execute(this);
     }
     else if (page.CurrentPage.TabIndex < currentPage)
     {
         PrevRegistrationPage?.Execute(this);
     }
     if (currentPage != page.CurrentPage.TabIndex)
     {
         page.CurrentPage = page.Children[currentPage];
     }
 }
 protected void NextPage(object sender, EventArgs e)
 {
     NextRegistrationPage?.Execute(this);
     page.CurrentPage = page.Children[currentPage];
 }