代表可以导致内存泄漏？ GC.TotalMemory（真）似乎表明这样(Can delegate

码

using System;
internal static class Test
{
    private static void Main()
    {
        try
        {
            Console.WriteLine("{0,10}: Start point", GC.GetTotalMemory(true));
            Action simpleDelegate = SimpleDelegate;
            Console.WriteLine("{0,10}: Simple delegate created", GC.GetTotalMemory(true));
            Action simpleCombinedDelegate = simpleDelegate + simpleDelegate + simpleDelegate;
            Console.WriteLine("{0,10}: Simple combined delegate created", GC.GetTotalMemory(true));
            byte[] bigManagedResource = new byte[100000000];
            Console.WriteLine("{0,10}: Big managed resource created", GC.GetTotalMemory(true));
            Action bigManagedResourceDelegate = bigManagedResource.BigManagedResourceDelegate;
            Console.WriteLine("{0,10}: Big managed resource delegate created", GC.GetTotalMemory(true));
            Action bigCombinedDelegate = simpleCombinedDelegate + bigManagedResourceDelegate;
            Console.WriteLine("{0,10}: Big combined delegate created", GC.GetTotalMemory(true));
            GC.KeepAlive(bigManagedResource);
            bigManagedResource = null;
            GC.KeepAlive(bigManagedResourceDelegate);
            bigManagedResourceDelegate = null;
            GC.KeepAlive(bigCombinedDelegate);
            bigCombinedDelegate = null;
            Console.WriteLine("{0,10}: Big managed resource, big managed resource delegate and big combined delegate removed, but memory not freed", GC.GetTotalMemory(true));
            GC.KeepAlive(simpleCombinedDelegate);
            simpleCombinedDelegate = null;
            Console.WriteLine("{0,10}: Simple combined delegate removed, memory freed, at last", GC.GetTotalMemory(true));
            GC.KeepAlive(simpleDelegate);
            simpleDelegate = null;
            Console.WriteLine("{0,10}: Simple delegate removed", GC.GetTotalMemory(true));
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
        Console.ReadKey(true);
    }
    private static void SimpleDelegate() { }
    private static void BigManagedResourceDelegate(this byte[] array) { }
}

产量

GC.TotalMemory(true)
    105776: Start point
    191264: Simple delegate created
    191328: Simple combined delegate created
 100191344: Big managed resource created
 100191780: Big managed resource delegate created
 100191812: Big combined delegate created
 100191780: Big managed resource, big managed resource delegate and big combined delegate removed, but memory not freed
    191668: Simple combined delegate removed, memory freed, at last
    191636: Simple delegate removed

Answer 1:

有趣的案例。这里是解决方案：

结合代表是观察性纯 ：它看起来像代表是不可改变到外部。但在内部，现有的代表正在修改 。他们共享，在一定条件下，同样_invocationList出于性能的考虑（优化这几个代表都挂在同一个事件的情况下）。不幸的是， _invocationList为simpleCombinedDelegate引用bigMgdResDelegate这将导致内存来维持生命。

Answer 2:

我会在这里失去了点，但垃圾收集是由设计不确定性。人机工程学，它是由.NET Framework来决定何时回收内存。

您可以在一个简单的循环运行GC.GetTotalMemory，并得到不同的数字。也许没有惊喜，如文档指定返回的数字是近似值。