Mixers can be modified by multiple applications. It is therefore sometimes important to know when a mixer has been modified by an application other than yours that is running at the same time.
The MSSMixer control provides the OnChange event to notify an application when the mixer is changed by any application (including the current application).
Note that the OnChange event is triggered whenever a control value is written, even if the new value of the control is the same as the old value. Care must therefore be taken if control values are modified within the OnChange event handler: you should only modify controls if the new value is not the same as the current value, otherwise an infinite loop of event triggers can result.