我有一个可观察到的来源Observablesource和执行功能voidExecute(Tt){....}我想编写一个vactivecommand，该触发时用最新值执行t。当没有可用值时，该命令不应执行看答案///CreateaReactiveCommandthatsamplesasourceobservable.The///sourceisimmediatelysubscribedtosothatwhenthecommand///isexecutedthepreviousvalueisavailabletotheexecution///function.publicstaticReactiv