What does ?? mean in C#?
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What do two question marks together mean in C#?
那是什么？？在这一陈述中的意思是？
1 | int availableUnits = unitsInStock ?? 0; |
coalescing this is the null operator。它translates to：
is used to change EN可空值类型的类型"。P＞＜／
1 2 3 4 | if (unitsInStock != null) availableUnits = unitsInStock; else availableUnits = 0; |
The ?? operator returns the left-hand operand if it is not null, or else it returns the right operand.
？经营者(C #参考)？P＞＜／
availableunits variable will be the en均值= = = = 0 unitsinstock除非unitsinstock，which is availableunits空房子。P＞＜／
根据MSDN，茶？is called the空？经营者和经营者coalescing is used to define a可空值类型的默认值来作为好作为参考类型。它的左操作数返回the if it is not null手数；otherwise the right恩归来。P＞＜／
退房msdn.microsoft.com http：/ / / / / ms173224.aspx恩-美国图书馆P＞＜／