我是否需要在每次“foreach"迭代时释放 COM 对象?

Do I need to release the COM object on every #39;foreach#39; iteration?(我是否需要在每次“foreach迭代时释放 COM 对象?)

问题描述

这是(潜在的)问题:

我创建了一个 COM 对象，然后使用foreach"遍历它返回的集合中的每个元素.我是否需要释放我在集合中遍历的每个单独元素?(见下面的代码.)如果是这样，我想不出一种方法可以有效地从finally"语句中释放它，以防在操作项目时出现错误.

I create a COM object, and then use a 'foreach' to iterate through each element in a collection it returns. Do I need to release each individual element I iterate through in the collection? (See code below.) If so, I can't think of a way to effectively to release it from within a 'finally' statement, just in case there is an error as the item is being operated upon.

有什么建议吗?

private static void doStuff()
{
    ComObjectClass manager = null;

    try
    {
        manager = new ComObjectClass();
        foreach (ComObject item in manager.GetCollectionOfItems())
        {
            Log.Debug(item.Name);
            releaseComObject(item); // <-- Do I need this line?
                                    //     It isn't in a 'finally' block...
                                    //             ...Possible memory leak?
        }
    }
    catch (Exception) { }
    finally
    {
        releaseComObject(manager);
    }
}

private static void releaseComObject(object instance)
{
    if (instance != null)
    {
        try
        {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(instance);
        }
        catch
        {
            /* log potential memory leak */
            Log.Debug("Potential memory leak: Unable to release COM object.");
        }
        finally
        {
            instance = null;
        }
    }
}

推荐答案

您不应该将 foreach 语句与 COM 对象一起使用，因为在您无法控制的幕后进行了引用过度释放.我会切换到 for 循环并确保您 永远不要在 COM 对象中使用两个点.

You should not use a foreach statement with a COM object, as a reference is made behind the scenes to which you have no control over releasing. I would switch to a for loop and make sure you never use two dots with COM objects.

看起来会是这样:

try
{
    manager = new ComObjectClass();
    ComObject comObject = null;
    ComObject[] collectionOfComItems = manager.GetCollectionOfItems();
    try
    {
        for(int i = 0; i < collectionOfComItems.Count; i++)
        {
            comObject = collectionOfComItems[i];
            ReleaseComObject(comObject);
        }
    }            
    finally
    {
        ReleaseComObject(comObject);
    }
}
finally 
{
    ReleaseComObject(manager);
}

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