Please find the code.
UserControl userControl = new UCTeamTweet();
userControl.Width = Convert.ToInt32("500");
userControl.Height = Convert.ToInt32("900");
userControl.HorizontalAlignment = HorizontalAlignment.Left;
userControl.VerticalAlignment = VerticalAlignment.Top;
stkPnlSearch.Children.Add(userControl);
Perform this action inside button_click event.