小编Ahm*_*mid的帖子

这是关于C#新引入的空检查运算符的问题.

假设我有一个界面,如:

interface ILogger
{
    void Log(string message);
}

和一个期望记录操作的函数:

void DoWork(Action<string> logAction)
{
    // Do work and use @logAction
}

如果我尝试编写,为什么会出现以下编译器错误:

void Main(string[] args)
{
    ILogger logger = GetLogger(); // Assume GetLogger() may return null

    //
    // Compiler error: 
    // Operator '?' cannot be applied to operand of type 'method group'
    //
    DoWork(logger?.Log);   
}

I have a situation where a project I'm maintaining contains a piece of code where:

1. A thread T1 periodically updates a field of type List<String> then adds a value to a LinkedBlockingQueue:

   // ctor
   List<String> list = null;
   queue = new LinkedBlockingQueue(); // Integer.MAX_VALUE capacity
   
   // Thread T1
   list = getNewList();
   queue.offer(/* some value */);
   

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2. Another thread T2 periodically polls queue and, upon receiving a certain value, reads list:

   // Thread T2
   Object value = queue.poll();
   if (Objects.equals(value, …

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