TextBlock with multiple lines by code on Windows Phone 8

Question

I have a string containing some text (note the \\n ),

string mText = "Hello\nWorld";

When I apply this to a TextBlock (generated by code) like this:

TextBlock tb = new TextBlock();
tb.Foreground = (Brush)App.Current.Resources["PhoneForegroundBrush"];
tb.FontSize = (double)App.Current.Resources["PhoneFontSizeMedium"];
tb.Margin = new Thickness(24, 32, 24, 12);
tb.TextWrapping = TextWrapping.Wrap;
tb.Text = mText;

I don't see the second line. Any ideas?

[UPDATE - Added the usage of this code]

I use this in showing a PopUp on the Screen:

// Create PopUp Content:
TextBlock tb = new TextBlock();
tb.Foreground = (Brush)App.Current.Resources["PhoneForegroundBrush"];
tb.FontSize = (double)App.Current.Resources["PhoneFontSizeMedium"];
tb.Margin = new Thickness(24, 32, 24, 12);
tb.TextWrapping = TextWrapping.Wrap;

tb.Text = pMessage;
Grid grid = new Grid();
grid.Background = (Brush)App.Current.Resources["PhoneAccentBrush"];
grid.Children.Add(tb);
grid.Width = page.ActualWidth;

// Create PopUp itself:
Popup popup = new Popup();
popup.Child = grid;

// Show PopUp:
SystemTray.BackgroundColor = (Color)App.Current.Resources["PhoneAccentColor"];
popup.IsOpen = true;

Answer 1

You could also add the following:

tb.Text = mText + Environment.NewLine;

or

tb.Text = mText + "
" + "
"

that seems to insert the <LineBreak/> into.