Download this extension from the VS Gallery or get the CI build.
Visual Studio Extension to compare two files in solution explorer.
See the changelog for changes and roadmap.
Select two files in solution explorer and right click to get Compare Files... option to compare the selected files.
When Compare Files... option selected, both the files will be opened in left panel and show the difference.
Feature to select second file from disk and compare. Select one file and right click to select "Compare Files..."
Get the comparison diff window
Check out the contribution guidelines if you want to contribute to this project.
For cloning and building this project yourself, make sure to install the Extensibility Tools 2015 extension for Visual Studio which enables some features used by this project.