如何检测 Windows 已完成添加/删除存储设备（不是作为驱动器号，仅作为设备）
我有一些装有简化 Windows 的计算机，其中添加/删除的存储设备不会自动获取驱动器号。 所以我必须找到一种方法来检测添加/删除的内容。 一种方法（我知道）是使用 WM_DEVICECHANGE 消息。 在这些计算机上，消息仅使用 WParam 7 和 LParam 0 发送到 Windows。 因此，当我的应用程序收到此消息时，我可以运行我的检测代码。 问题是设备需要一些时间才能被完全识别；与此同时，我的应用程序受到 WM_DEVICECHANGE 消息“齐射”的“轰炸”，检测代码甚至启动了 6..7 次。 为了解决这个问题，我可以添加一个由新消息重新初始化的计时器；如果一段时间（1..2 秒）后，应用程序没有收到消息，则启动检测代码。 但我百分百不喜欢这种方法，因为它没有考虑其他因素，例如：计算机的速度、其他降低 Windows 速度的程序、不同的存储设备类型等。事实上，检测代码在延迟有点烦人。
有人知道更专业的解决方案吗...？
感谢您的帮助。
I have some computers with a simplified Windows in which storage devices that are added/removed don't get automatically drive letters.
So I have to find a way to detect that are added/removed.
One way (that I know) is with WM_DEVICECHANGE message.
On those computers the message is sent to windows only with WParam 7 and LParam 0.
So I could run my detection code when this message is received by my application.
The problem is that it takes some time for the device to be completely recognized; meantime my application is "bombarded" with a "salvo" of WM_DEVICECHANGE messages and the detection code is started even 6..7 times.
To solve I could add a timer who is reinitialized by a new message; if, after some time (1..2 sec), the application is not receiving the message, the detection code is started.
But I don't like this approach 100% because it doesn't take into consideration other factors as: the speed of the computer, other programs that slow down Windows, different storage device types etc. And the fact that the detection code finishes after a delay it's a little annoying.
Does anybody know a more professional solution...?
Thank you for any help.
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我昨天正在处理这些消息，在我的测试程序中，如果我过滤消息，我只会收到一条用于添加的消息和一条用于删除的消息。
请参阅我的博客更详细的描述。
I was playing with this these messages yesterday and in my testprogram I get only one message for adding and one for removal if I filter the messages.
See my blog for a more detailed description.
确实，在大多数情况下您会收到大量消息。我的解决方案与您的类似，只是我使用了线程而不是计时器。在这种情况下，我的等待时间是 15 秒（在 DBT_DEVICEARRIVAL 之后）。
事实上，当我查看您问题的措辞时，DBT_DEVICEARRIVAL 正是您正在寻找的。即使随后出现更多通知，设备此时仍可用。插入 USB 闪存盘时，我收到以下信息：
出于您的目的，DBT_DEVNODES_CHANGED 通知是无关紧要的。您只对 DBT_DEVICEARRIVAL（用 Delphi 的说法是 $8000）感兴趣。
此外，如果您通过消息的符号名称而不是编号来引用消息，那将会非常有帮助。
It's true, for most cases you get numerous messages. My solution to this was similar to yours, except that instead of the timer I used a thread. My waiting time was 15s in this case (after DBT_DEVICEARRIVAL).
In fact DBT_DEVICEARRIVAL is exactly the one you're looking for when I look at the wording of your question. The device is available at that time, even if more notifications follow. I get the following when plugging in a USB key:
For your purpose the DBT_DEVNODES_CHANGED notifications are irrelevant. You are interested solely in DBT_DEVICEARRIVAL ($8000 in Delphi parlance).
Besides, it would really help if you would refer to the messages by their symbolic name, not their number.