In my answer i will discuss 2 ways to get rid of the changes you made and reset back to what is in the code repo. First is the way to reset all files at once. The second method is how to do 1 single file if that is all that is needed.

METHOD 1, ALL FILES AT ONCE:

Click the Home button on the Team Explorer and see this screen:

Then click Branches to see this screen:

Then right-click the branch you want to revert your local code to and select Reset and then Delete Changes (–hard):

METHOD 2, Single file at a time:

Now you may want to just revert a single file and this is done by doing the following:

Click Home button on your Team Explorer and see this page:

Then click Changes and see this screen:

Then right-click any of the files you have listed there and select Undo Changes…