Question

for (int i = 0; i < list.Count; i++) {
  ds = new Discription();

  PivotItem pivotItem = new PivotItem();
  pivotItem.Header = list.ElementAt(i).header.ToString();

  StackPanel sta = new StackPanel();
  WebBrowser wb = new WebBrowser();

  sta.Children.Add(wb);

  pivotItem.Content = sta;         
  Pivot_item1.Items.Add(pivotItem);
  wb.NavigateToString(list.ElementAt(i).Detail.ToString());
}

an error is occur when calling web browser control
You cannot call WebBrowser methods until it is in the visual tree.

Answer 1

Subscribe to the Loaded event of the Webbrowser control and move your navigation code to the loaded handler.

Replace the line

wb.NavigateToString(list.ElementAt(i).Detail.ToString());

with

var address = list.ElementAt(i).Detail.ToString();
wb.Loaded += (sender, e) => { wb.NavigateToString(address); }