Team Foundation Server 2012 introduced the concept of local workspaces. A local workspace offers several advantages compared to a server workspace. It allows you to work offline easily. You can perform core version control operations even when you're not connected to your Team Foundation Server.
By default certain types of files (for example, .dll files) are ignored by version control(this information is stored in the registry). So if you want to change the list of files that are excluded, you can change the registry key.
However this is not the only way: you can also specify which kinds of files are ignored by placing text file called .tfignore in the folder where you want rules to apply. The effects of the .tfignore file are recursive. However, you can create .tfignore files in sub-folders to override the effects of a .tfignore file in a parent folder.(This is similar to what a .gitignore file does in GIT)
The following rules apply to a .tfignore file:
# begins a comment line
The * and ? wildcards are supported.
A filespec is recursive unless prefixed by the \ character.
! negates a filespec (files that match the pattern are not ignored)