createAsync method
Creates a RxCommand for an asynchronous handler function with no parameter and no return type
action
: handler function
canExecute
: observable that can bve used to enable/diable the command based on some other state change
if omitted the command can be executed always except it's already executing
Implementation
static RxCommand<Null, Null> createAsync(AsyncAction action,[Observable<bool> canExecute])
{
return new RxCommandAsync<Null,Null>((_) { action(); return null;},canExecute);
}