What is the movie starring Jeff chandler and featuring beethoven moonlight sonata played on an upright piano in a western saloon?

The movie you are referring to is "Broken Arrow" (1950). It stars James Stewart and Jeff Chandler, not Jeff Chandler and James Stewart. In the film, Chandler's character, Cochise, plays Beethoven's Moonlight Sonata on an upright piano in a Western saloon.