MessageBox.Show 阻止当前线程，直到用户关闭该消息。工作线程在被阻止时无法处理取消请求。



从工作线程显示模态消息也可能不是一个好主意。它可能会产生意想不到的后果：

MessageBoxes和工作线程 [ ^ ]



你在做什么似乎是一个非常糟糕的主意。您真的希望用户必须单击确定1000次吗？

MessageBox.Show blocks the current thread until the message is closed by the user. The worker thread cannot process the cancellation request whilst it is blocked.

It's also probably not a good idea to show a modal message from a worker thread. It could have unintended consequences:
MessageBoxes and worker threads[^]

What you're doing seems like a very bad idea. Do you really want your users to have to click "OK" 1000 times?