问题：

Ran across this line of code: 跨越这行代码：

FormsAuth = formsAuth ?? new FormsAuthenticationWrapper();

What do the two question marks mean, is it some kind of ternary operator? 这两个问号意味着什么，是某种三元运算符？ It's hard to look up in Google. 谷歌很难找到。

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解决方案：

参考一： https://stackoom.com/question/1sF1/C-中两个问号共同意味着什么
参考二： https://oldbug.net/q/1sF1/What-do-two-question-marks-together-mean-in-C