When trying to change an icon in a TextBox using the Segoe MDL2 Assets, it just give me some ugly squares.
The solution is to use the escape character followed by the Unicode representation of the icon.
MyTextBox.Content = "\uE71A";
And not to use the classical notation &#…
Thanks to this guy : https://www.youtube.com/watch?v=SOkOjjEQzxc
Just a post it to this page that contains guidelines and is like a cheat sheet for the icons that developers can use with Windows Universal Apps, using the Segoe MDL2 Assets font.
Also this page
<Button FontFamily="Segoe MDL2 Assets" Content="& #xE001;" FontSize="36"/>
Note REMOVE THE SPACE CHARACTER in the content. I added this because it wasn’t readable otherwise…