Question

In method that is working in the background, i have two important lines :

createPopup();
MessageBox.Show(sth);
more lines
more lines

createPopup() just creates a popup, adds a grid as a child and shows popup.
My question is, why first shows up messageBox, then shows up Popup, which appears after all lines in this method done ? How could I make this popup to show before all lines in this method will be done ?

Answer 1

Creating the pop-up, does not actually draw it on the screen until the Layout event. If you want to ensure that the pop-up has been drawn before you display the pop-up, attach an event handler to the pop-up’s LayoutUpdated event and display the message box from within that event handler. Be sure to detach the event handler as well or you will see multiple message boxes.

public InitPage()
{
   Popup popup = new Popup();
   popup.LayoutUpdated += popup_LayoutUpdated;
   LayoutRoot.Controls.Add(popup);
}

void popup_LayoutUpdated(object sender, object e)
{
     popup_LayoutUpdated -= popup_LayoutUpdated;
     MessageBox.Show("hello");
}