Using Visual Studio 2013 and TFS I did a lot of work before checking in. Then I accidentally clicked undo pending changes... thinking it would only apply to one of the proje
Just for your help. As per stackoverflow's questions link shared. He is trying to say that if you have not build your project. You can open last built dll in Reflector and see the code of the files and recover the code.
You can use any took like Reflector or dotpeek from JetBrains.
Visit this link to know more about dotpeek
But if you have build your project after performing Undo Pending changes then as per my knowledge it is impossible to get the code.