c# - 弱引用的线程安全

Question

使用 Wea​​kReference 时，我们如何确定在 .IsAlive 和 .Target 调用之间没有收集到目标？

例如:

if (myWeakReference.IsAlive)
{
    // How can we be sure the object is still alive while here?
    ((MyType)myWeakReference.Target).Foo();
}

Answer 1

只需获取 Target 并检查它是否不为空:

object target = myWeakReference.Target;
if (target != null)
{        
    ((MyType)target).Foo();
}

docs for IsAlive具体来说:

Because an object could potentially be reclaimed for garbage collection immediately after the IsAlive property returns true, using this property is not recommended unless you are testing only for a false return value.