if (user?.Identity?.IsAuthenticated ?? false)这几个问号分别都代表啥意思？

if (user?.Identity?.IsAuthenticated ?? false)这几个问号分别都代表啥意思？

0

悬赏园豆：5
[已解决问题]
浏览: 229次
解决于 2018-05-16 13:27

            var user = HttpContext.User;
            if (user?.Identity?.IsAuthenticated ?? false)
            {

            }
            else
            {

            }

如题，求解。

屌丝大叔的笔记
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初学一级
|
园豆：67

提问于：2018-05-16 10:26

牛逼的写法，谢谢dudu，xiexie演员。

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屌丝大叔的笔记

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最佳答案

1

? 如果不为null，执行其后的方法；?? 如果为null，返回其后的值。

        <div id="answer_option_226950">
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等价于

         bool isNull;
            if (user != null)
            {
                if (user.Identity != null)
                {
                    if (user.Identity.IsAuthenticated != null)
                    {
                        isNull = user.Identity.IsAuthenticated;
                    }
                }
            }
            isNull = false;
            if (isNull)
            {
        } </span></pre>

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园豆：541
(小虾三级)
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2018-05-16 11:38

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posted @
2019-07-11 15:05 
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