这只是调试消息。您可以通过右键单击进入输出窗口将其关闭，然后取消选中线程退出消息。

This is just debugging message. You can switch that off by right clicking into the output window and uncheck Thread Exit Messages.

http://msdn.microsoft.com/en-us/library/bs4c1wda.aspx

除了从应用程序中进行编程外，输出窗口
还可显示有关：

In addition to program out from your application, the Output window can display the information about:

• 调试器已加载或卸载的模块。

• Modules the debugger has loaded or unloaded.

引发的异常。

退出的进程。

退出的线程。