how can i display two user controls inside a popup and show

You can archive this by using the below method

Write the code in your button click event 

{
MessageDialog msg;
msg = new MessageDialog("Hint Message?");
UICommand okbtn = new UICommand("YES");
okbtn.Invoked = OKBUTNCLICK;
msg.Commands.Add(okbtn);

UICommand cancelbtn = new UICommand("NO");
cancelbtn.Invoked = CancelClick;
msg.Commands.Add(cancelbtn);
await msg.ShowAsync();
}

private void CancelClick(IUICommand command)
{
///write the code for popup 1///
}

private void OKBUTNCLICK(IUICommand command)
{
//write the code for popup 2//
}