When these messages are processed, you are back in the context of thread A and calls to CWnd::AssertValid() to check thread A's window handle maps will succeed.

在处理窗口消息时，系统已经切换到线程A。这是验证窗口对象的有效性会成功。

youdao

Points to the parent window object (of type CWnd) to which the dialog object belongs. If it is NULL, the dialog object's parent window is set to the main application window.

指向含有对话框地父窗口对象地指针。假如为NULL，对话框对象地父窗口设置为应用地主窗口。

youdao

Points to the parent window object (of type CWnd) to which the dialog object belongs. If it is NULL, the dialog object's parent window is set to the main application window.

指向含有对话框地父窗口对象地指针。假如为NULL，对话框对象地父窗口设置为应用地主窗口。

youdao