viewmodel - Bind to IReactiveCommand in view code behind -

i have viewmodel has errorcommand. wish subscribe in view code behind time called can display error message passed so:

errorcommand.exectute("error occured") 

in view:

this.whenany(view => x.viewmodel.errorcommand, x => x.value).subscribe(error => displayerror(error)); 

this code doesn't work shows i'm trying acheive. how correctly?

i understand use messagebus, have similar scenario messagebus wouldn't appropriate.

there's method scenario:

this.whenanyobservable(x => x.viewmodel.errorcommand).subscribe(x => /* ... */); 

will expect , avoid null refs