数据集通过MarshalByValueComponent实现IDisposable，它实现了IDisposable。因为数据集是管理的，所以调用dispose并没有真正的好处。

数据集通过MarshalByValueComponent实现IDisposable，它实现了IDisposable。因为数据集是管理的，所以调用dispose并没有真正的好处。

更新(2009年12月1日):

我想修改这个答案，并承认原来的答案有缺陷。

最初的分析确实适用于需要最终确定的对象——没有准确、深入的理解，实践不应该在表面上被接受的观点仍然成立。

然而，数据集、数据视图、数据表在它们的构造函数中抑制了终结——这就是为什么显式地在它们上调用Dispose()不做任何事情。

据推测，这是因为它们没有非托管资源;因此，尽管MarshalByValueComponent允许使用非托管资源，但这些特定的实现不需要，因此可以放弃终结。

(. net作者会注意抑制通常占用最多内存的类型的终结，这说明了这种实践对于可终结类型的重要性。)

尽管如此，自从。net框架出现以来(大约8年前)，这些细节仍然没有得到充分的记录，这是相当令人惊讶的(你基本上只能靠自己的设备来筛选相互冲突的、模糊的材料，然后把它们拼凑在一起，这有时令人沮丧，但确实提供了对我们每天所依赖的框架的更完整的理解)。

经过大量阅读，我的理解如下:

If an object requires finalization, it could occupy memory longer than it needs to – here’s why: a) Any type that defines a destructor (or inherits from a type that defines a destructor) is considered finalizable; b) On allocation (before the constructor runs), a pointer is placed on the Finalization queue; c) A finalizable object normally requires 2 collections to be reclaimed (instead of the standard 1); d) Suppressing finalization doesn’t remove an object from the finalization queue (as reported by !FinalizeQueue in SOS) This command is misleading; Knowing what objects are on the finalization queue (in and of itself) isn’t helpful; Knowing what objects are on the finalization queue and still require finalization would be helpful (is there a command for this?) Suppressing finalization turns a bit off in the object's header indicating to the runtime that it doesn’t need to have its Finalizer invoked (doesn’t need to move the FReachable queue); It remains on the Finalization queue (and continues to be reported by !FinalizeQueue in SOS)

DataTable, DataSet, DataView类都植根于MarshalByValueComponent，这是一个可以(潜在地)处理非托管资源的可终结对象

Because DataTable, DataSet, DataView don’t introduce unmanaged resources, they suppress finalization in their constructors While this is an unusual pattern, it frees the caller from having to worry about calling Dispose after use This, and the fact that DataTables can potentially be shared across different DataSets, is likely why DataSets don’t care to dispose child DataTables This also means that these objects will appear under the !FinalizeQueue in SOS However, these objects should still be reclaimable after a single collection, like their non-finalizable counterparts

4(新参考资料):

http://www.devnewsgroups.net/dotnetframework/t19821-finalize-queue-windbg-sos.aspx http://blogs.msdn.com/tom/archive/2008/04/28/asp-net-tips-looking-at-the-finalization-queue.aspx http://issuu.com/arifaat/docs/asp_net_3.5unleashed http://msdn.microsoft.com/en-us/magazine/bb985013.aspx http://blogs.msdn.com/tess/archive/2006/03/27/561715.aspx

最初的回答:

关于这个问题有很多误导性的答案，通常都很糟糕——任何登陆这里的人都应该忽略噪音，仔细阅读下面的参考资料。

毫无疑问，Dispose应该在任何可终结对象上被调用。

我被冒犯了

调用Dispose可以显著加快内存的回收速度。

MarshalByValueComponent在Dispose()中调用GC.SuppressFinalize(this)——跳过这个意味着在内存回收之前必须等待几十个(如果不是数百个)Gen0集合:

With this basic understanding of finalization we can already deduce some very important things: First, objects that need finalization live longer than objects that do not. In fact, they can live a lot longer. For instance, suppose an object that is in gen2 needs to be finalized. Finalization will be scheduled but the object is still in gen2, so it will not be re-collected until the next gen2 collection happens. That could be a very long time indeed, and, in fact, if things are going well it will be a long time, because gen2 collections are costly and thus we want them to happen very infrequently. Older objects needing finalization might have to wait for dozens if not hundreds of gen0 collections before their space is reclaimed. Second, objects that need finalization cause collateral damage. Since the internal object pointers must remain valid, not only will the objects directly needing finalization linger in memory but everything the object refers to, directly and indirectly, will also remain in memory. If a huge tree of objects was anchored by a single object that required finalization, then the entire tree would linger, potentially for a long time as we just discussed. It is therefore important to use finalizers sparingly and place them on objects that have as few internal object pointers as possible. In the tree example I just gave, you can easily avoid the problem by moving the resources in need of finalization to a separate object and keeping a reference to that object in the root of the tree. With that modest change only the one object (hopefully a nice small object) would linger and the finalization cost is minimized. Finally, objects needing finalization create work for the finalizer thread. If your finalization process is a complex one, the one and only finalizer thread will be spending a lot of time performing those steps, which can cause a backlog of work and therefore cause more objects to linger waiting for finalization. Therefore, it is vitally important that finalizers do as little work as possible. Remember also that although all object pointers remain valid during finalization, it might be the case that those pointers lead to objects that have already been finalized and might therefore be less than useful. It is generally safest to avoid following object pointers in finalization code even though the pointers are valid. A safe, short finalization code path is the best.

从那些在第2代中看过100多mb的非引用数据表的人那里吸取经验:这是非常重要的，并且完全被本文的答案遗漏了。

引用:

1 - http://msdn.microsoft.com/en-us/library/ms973837.aspx

2 - http://vineetgupta.spaces.live.com/blog/cns! 8DE4BDC896BEE1AD! 1104.entry http://www.dotnetfunda.com/articles/article524-net-best-practice-no-2-improve-garbage-collector-performance-using-finali zedispose-pattern.aspx

3 - http://codeidol.com/csharp/net-framework/Inside-the-CLR/Automatic-Memory-Management/

尝试使用Clear()函数。 这对我来说很有用。

DataTable dt = GetDataSchema();
//populate dt, do whatever...
dt.Clear();

每当一个对象实现IDisposeable时，我就调用dispose。它的存在是有原因的。

数据集可能占用大量内存。它们越早被标记为清理越好。

更新

我已经5年没有回答这个问题了。我仍然同意我的答案。如果存在dispose方法，则应该在处理完对象时调用该方法。实现IDispose接口是有原因的。

您应该假设它做了一些有用的事情并调用Dispose，即使它在当前的. net Framework版本中什么也不做。并不能保证它在未来的版本中会保持这种方式，从而导致低效的资源使用。