我正在尝试计算“observableArray”的“价格”字段的总和。到目前为止,我有以下代码:(function(){functionobjFeatures(name,price){return{name:ko.observable(name),price:ko.observable(price),removeFeatures:function(){appViewModel.features.remove(this);}}}varappViewModel={features:ko.observableArray([newobjFeatures("Feature1",20),newob