Question

我在JS中有以下内容：

function reportCriteria(fieldId,fieldName,filterOption,optionText,filterChoice) {
        return {
            fieldId: fieldId
            fieldName: fieldName,
            filterOption: filterOption,
            optionText: optionText,
            filterChoice: filterChoice,
            description: ko.computed(function () {
                return fieldName + " which " + optionText + " " + filterChoice;
            })
        };
    }

我的模型中有一个observableArray，它包含了我推送的内容：model.criteriaEntries.push（new reportCriteria（paramshere））;

所有看起来都没问题，直到我尝试编辑这样的：

var criItem = ko.utils.arrayFirst(model.criteriaEntries(), function (item) {
            return item.fieldId == id;
        });
        if (criItem) {
            criItem.filterOption = option;
            criItem.optionText = opttext;
            criItem.filterChoice = choice;
            model.criteriaEntries.valueHasMutated();
        }

我没有错误，我可以调试并看到对象已更改，但计算的描述没有更新，因为尽管添加了valueHasMutated，屏幕上没有任何变化？

Answer 1

你的问题是你通过criItem.optionText = opttext覆盖了optionText;

不要那样做。而是更新optionText：

criItem.optionText(opttext);

然后您的计算将相应更新。

修改以下是您的报告创建代码应如下所示：

function reportCriteria(fieldId,fieldName,filterOption,optionText,filterChoice) {
    var report = {
       fieldId: fieldI),
       fieldName: fieldName,
       filterOption: ko.observable(filterOption),
       optionText: ko.observable(optionText),
       filterChoice: ko.observable(filterChoice)
    };
    report.description = ko.computed(function () {
       return report.fieldName + " which " + report.optionText() + " " + report.filterChoice();
    });
    return report;
}

以下是编辑方法：

var criItem = ko.utils.arrayFirst(model.criteriaEntries(), function (item) { return item.fieldId == id; });
if (criItem) {
   criItem.filterOption(option);
   criItem.optionText(opttext);
   criItem.filterChoice(choice);
}

Knockout计算不更新

1 个答案: