File type definitions allow you to customize the way Team Foundation version control processes files with specific extensions. By defining a file type, you can disable files with certain extensions from being merged and thereby, prevent multiple users from checking them out in parallel.
By default, file merging and multiple check-out is enabled.
Multiple check-out can be disabled at the team project level.
A Team Foundation file type definition consists of three properties. The most important of these properties is File Extension, which is the unique identifier for a file type.
Visual Basic File
Enable File Merging and Multiple Checkout
As a Team Foundation administrator, you might want to specify that files of certain types, such as binary Microsoft Excel files (*.xls) for which a merging tool does not exist, cannot be merged when conflicts are detected and can only be checked out by one user at a time. You can control this by selecting Enable File Merging and Multiple Checkout in the Edit File Type dialog box. For more information, see How to: Edit File Type Association with Team Foundation Version Control. If a file type does not exist for a given extension, files with that extension can be merged.
In addition to these basic file type properties, Team Foundation also tracks the file encoding for each file on the version control server. You can override the default encoding for a file from the version control Properties window opened from Source Control Explorer, or using the command line interface. For more information, see How to: Configure Version Control File Encoding and Checkout and Edit Commands.