Compare two xml files and highlight the differences

I could use some help with something i need to solve. I have two xml files and they are almost identical, i need to find what was changed, which means, i need to compare them line by line, and i need to highlight the changes in Visual Studio using c#

I've seen the tools but i would like to know if i can do it using code. I'm new to this so i could use a little guide.

My xml files are something like:

<PAGE>
  <SHEET>
     <BUTTON>
     <BUTTON>
     <BUTTON>
  <SHEET>
<PAGE>