Enables background tasks that interact with the userinterface, communicating via events raised on the user-interfacethread.
启用与使用者介面互动的背景工作，透过使用者介面执行绪上引发的事件来沟通。
2
A user-interfacethread is commonly used to handle user input and respond to user events independently of threads executing other portions of the application.
使用者介面执行绪通常用来处理使用者输入和回应与执行绪没有关系之执行应用程序其他部分的使用者事件。
3
This is because remote invocations in JSR 172 are blocking calls, and if invoked in the main event thread, the userinterface will freeze until the remote invocation completes.