我需要在每个'foreach'迭代释放COM对象吗？ [英] Do I need to release the COM object on every 'foreach' iteration?

问题描述

这里是（潜在的）问题：

我创建一个COM对象，然后使用一个foreach遍历它返回的集合中的每个元素。我需要释放在集合中迭代的每个单独的元素吗？ （见下面的代码。）如果是这样，我不能想办法有效地从一个'finally'语句中释放它，只是为了在项目被操作时出现错误。

有任何建议吗？

  private static void doStuff（）
 {
 ComObjectClass manager = null; 
 
 try 
 {
 manager = new ComObjectClass（）; 
 foreach（manager.GetCollectionOfItems（）中的ComObject项）
 {
 Log.Debug（item.Name）; 
 releaseComObject（item）; //<  - 我需要这行吗？ 
 //它不在一个'finally'块... 
 // ...可能的内存泄漏？ 
} 
} 
 catch（Exception）{} 
 finally 
 {
 releaseComObject（manager）; 
} 
} 
 
 private static void releaseComObject（object instance）
 {
 if（instance！= null）
 {
 try 
 {
 System.Runtime.InteropServices.Marshal.ReleaseComObject（instance）; 
} 
 catch 
 {
 / * log潜在内存泄漏* / 
 Log.Debug（潜在内存泄漏：无法释放COM对象。 
} 
 finally 
 {
 instance = null; 
} 
} 
} 
  

解决方案>

你不应该使用带有COM对象的 foreach 语句，因为引用是在你没有控制释放的场景之后。我将切换到 for 循环，并确保您从不使用两个点与COM对象。

这样看起来将是：

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

Here's the (potential) problem:

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.

Any suggestions?

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;
        }
    }
}

解决方案

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.

The way this would look would be:

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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