Question

我们可以改进这行代码

if ((l_Subscription.PackageInfo.Applications.Where(x => x.DeviceType != DeviceType.UnKnown)).Count() > 0)
        {
            //l_Subscription.DeviceTypeID = ((l_Subscription.PackageInfo.Applications.Where(x => x.DeviceType == DeviceType.Tablet)).Count() > 0)?()
            if ((l_Subscription.PackageInfo.Applications.Where(x => x.DeviceType == DeviceType.Tablet)).Count() > 0)
                l_Subscription.DeviceTypeID = (int)DeviceType.Tablet;
            else if ((l_Subscription.PackageInfo.Applications.Where(x => x.DeviceType == DeviceType.Phone)).Count() > 0)
                l_Subscription.DeviceTypeID = (int)DeviceType.Phone;
        }

我刚试过以下但没有工作......需要帮助

int cnt =  DoOperation(l_Subscription.PackageInfo.Applications, x => x.DeviceType != DeviceType.UnKnown);
       if(cnt > 0)
       {
           int cnt1 =  DoOperation(l_Subscription.PackageInfo.Applications, x => x.DeviceType == DeviceType.Tablet);
           int cnt2 =  DoOperation(l_Subscription.PackageInfo.Applications, x => x.DeviceType == DeviceType.Phone);

           if(cnt1 > 0) l_Subscription.DeviceTypeID = (int)DeviceType.Tablet;
           else if (cnt2 > 0) l_Subscription.DeviceTypeID = (int)DeviceType.Phone;           
       }

        private int DoOperation<TKey>(List<l_Subscription.PackageInfo.Applications> list, Func<l_Subscription.PackageInfo.Applications, TKey> predicate)
        {        
            int count = 0;
            count = list.Where(predicate).Count();
            return count;
        }

Answer 1

一个简单的改进就是替换

.Where( predicate ).Count() > 0

与

.Any( predicate )

哦，如果那是你的所有代码，你可以删除外部if，因为内部if条件和内部else条件都暗示外部if条件，给你：

if ((l_Subscription.PackageInfo.Applications.Any(x => x.DeviceType == DeviceType.Tablet))
    l_Subscription.DeviceTypeID = (int)DeviceType.Tablet;
else if ((l_Subscription.PackageInfo.Applications.Any(x => x.DeviceType == DeviceType.Phone))
    l_Subscription.DeviceTypeID = (int)DeviceType.Phone;

Answer 2

IF Application集合将始终只包含一个DeviceType（意味着同一集合中没有Tablets和Phones的混合），然后可以将上述内容缩短为：

   l_Subscription.DeviceTypeID = l_Subscription.PackageInfo.Applications.First(x => x.DeviceType == DeviceType.Tablet || x.DeviceType == DeviceType.Phone);

当然只有你知道这对你的场景是否是一个合理的假设......

我们如何改进以下代码？

2 个答案: