I need a C# windows forms application (with source code & documentation) for capturing still images and saving in the PC from a standard USB webcam using an external snap shot button on the camera. The trigger is hardware (external button on the camera) and not software (button on UI). I do not need live streaming of the images from the webcam. This should work with any standard web cam, ie using standard windows drivers and should not be dependent the manufacturer.
The application should work on Windows XP, VISTA and Windows 7.