c# - GC 根和局部变量

Question

同时查看 Timer documentation我遇到了以下带有此评论的示例:

    // Normally, the timer is declared at the class level,
    // so that it stays in scope as long as it is needed.
    // If the timer is declared in a long-running method,  
    // KeepAlive must be used to prevent the JIT compiler 
    // from allowing aggressive garbage collection to occur 
    // before the method ends. You can experiment with this
    // by commenting out the class-level declaration and 
    // uncommenting the declaration below; then uncomment
    // the GC.KeepAlive(aTimer) at the end of the method.
    //System.Timers.Timer aTimer;
    code in between
    // If the timer is declared in a long-running method, use
    // KeepAlive to prevent garbage collection from occurring
    // before the method ends.
    //GC.KeepAlive(aTimer);

这是否意味着 C# 中的 GC 可以对局部变量进行垃圾回收，即使它会产生副作用？大概是因为我之后不再访问计时器，GC 可以更早地收集它吗？

不确定我是否喜欢这种优化，如果我理解正确(但我可能不理解；))

Answer 1

是的，GC 可能会在作用域结束前收集局部变量，在最后一次使用变量后立即收集。将 GC.KeepAlive 放在方法的末尾可确保变量在调用 KeepAlive 之前一直处于“事件”状态。

C# 是命令式语言，因此 GC 并未设计为了解任何副作用。