如果我在c＃中关闭应用程序，是否有必要释放ComObject？

Question

我有以下代码，我想知道是否需要手动释放ComObject，否则垃圾收集器会为我发布它？

wordApp = new Word.Application();
wordDoc = new Word.Document();
// some stuff

wordDoc.Close(null, null , null);
wordApp.Quit();
if(System.Runtime.InteropServices.Marshal.IsComObject(wordDoc))
    System.Runtime.InteropServices.Marshal.ReleaseComObject(wordDoc);
wordDoc = null;
if (System.Runtime.InteropServices.Marshal.IsComObject(wordApp))
    System.Runtime.InteropServices.Marshal.ReleaseComObject(wordApp);
wordApp = null;

上述代码是否正确或最终我不应该使用Marshal.IsComObject？