That's not exactly the recommended way of populating a text box. Rather than "Keys" try "SetText". However, it's odd that it's grabbing a value from a completely different CSV... could you give your code in context so we can see what's going on? It would be easier to debug if we saw more of what's happening.
Why automate? I do automated testing because there's only so much a human being can do and remain healthy. Sleep is a requirement. So, while people sleep, automation that I create does what I've described above in order to make sure that nothing gets past the final defense of the testing group. I love good food, good books, good friends, and good fun.