javascript - 从javascript中的对象获取值

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我有几个对象作为这种结构:

然后我创建一个函数来更新与搜索 ID 匹配的商品数量:

function setQuantityInCartByID(json, itemID, val){
    for(var i in json){
        console.log(json[i].ID);
        if(json[i].ID == itemID){
           json[i].QuantityInCart = val;
           break;
        }
     }
     return json;
}

这是我的 JSON ；

{"DepartmentID":12,"CategoryID":117,"BrandID":19,"BrandImage":"         ","BrandName":"General","ID":708,"Name":"Grand 6Port Power Center","PictureName":"http://111.92.241.110/wwwProducts/unknown.PNG","Notes":"","PriceShow":"$10.00","Price":0,"PriceA":0,"PriceB":0,"PriceC":0,"WebsitePrice":0,"Quantity":2,"QuantityInCart":2,"LastUpdated":"/Date(1378108144050)/","Active":1,"PriceLevel":0,"NewProductImage":"http://111.92.241.110/wwwProducts/newproduct.png","isNewProduct":false,"isInStock":"10 Available in Stock(s)!","NewArrival":0,"ExpireNewArrival":"/Date(-62135596800000)/","NewPromotion":0,"ExpireNewPromotion":"/Date(-62135596800000)/"}

{"DepartmentID":12,"CategoryID":117,"BrandID":19,"BrandImage":"         ","BrandName":"General","ID":709,"Name":"Grand 6Port Power Center","PictureName":"http://111.92.241.110/wwwProducts/unknown.PNG","Notes":"","PriceShow":"$10.00","Price":0,"PriceA":0,"PriceB":0,"PriceC":0,"WebsitePrice":0,"Quantity":2,"QuantityInCart":2,"LastUpdated":"/Date(1378108144050)/","Active":1,"PriceLevel":0,"NewProductImage":"http://111.92.241.110/wwwProducts/newproduct.png","isNewProduct":false,"isInStock":"10 Available in Stock(s)!","NewArrival":0,"ExpireNewArrival":"/Date(-62135596800000)/","NewPromotion":0,"ExpireNewPromotion":"/Date(-62135596800000)/"}       

{"DepartmentID":12,"CategoryID":117,"BrandID":19,"BrandImage":"         ","BrandName":"General","ID":710,"Name":"Grand 6Port Power Center","PictureName":"http://111.92.241.110/wwwProducts/unknown.PNG","Notes":"","PriceShow":"$10.00","Price":0,"PriceA":0,"PriceB":0,"PriceC":0,"WebsitePrice":0,"Quantity":2,"QuantityInCart":2,"LastUpdated":"/Date(1378108144050)/","Active":1,"PriceLevel":0,"NewProductImage":"http://111.92.241.110/wwwProducts/newproduct.png","isNewProduct":false,"isInStock":"10 Available in Stock(s)!","NewArrival":0,"ExpireNewArrival":"/Date(-62135596800000)/","NewPromotion":0,"ExpireNewPromotion":"/Date(-62135596800000)/"}

问题:console.log(json[i].ID);结果未定义。

Answer 1

我认为您不需要 for in 循环。看起来你的参数 json 已经是一个对象了，所以不需要循环，只需要 json.ID