C#内存缓存资源边界

请注意,DataTable没有任何可处理的非托管资源( explained well in this post ).

引用类型(如DataTable)作为对所添加对象的引用添加到MemoryCache。对象保留在相同的资源空间中。

下面是一个简单的POCO来说明这种行为:

class SimpleClass
    {
        public string someText { get; set; }
    }

    static void Main()
    {
        var cache = MemoryCache.Default;
        var simpleObject = new SimpleClass { someText = "starting text" };
        SimpleClass cachedContent = null;

        CacheItemPolicy policy = new CacheItemPolicy();

        cache.Add("mykey", simpleObject, policy);

        // Expect "starting text" output
        cachedContent = (SimpleClass) cache.Get("mykey");
        Console.WriteLine(cachedContent.someText);

        simpleObject.someText = "new text";

        // Now it will output "new text"
        cachedContent = (SimpleClass)cache.Get("mykey");
        Console.WriteLine(cachedContent.someText);

        // simpleObject points nowhere now but object still exists, 
        // pointed to by cache item so will still output "new text"
        simpleObject = null;
        cachedContent = (SimpleClass)cache.Get("mykey");
        Console.WriteLine(cachedContent.someText);
    }