来自菜单、加速键或工具栏按钮的消息。这类消息都以WM_COMMAND呈现。在MFC中，通过菜单项的标识（ID）来区分不同的命令消息；在SDK中，通过消息的wParam参数识别。-From the menu or toolbar button to speed up the key message. Such messages are presented in WM_COMMAND. In MFC, a menu item through the identification (ID) to distinguish between different command message　in the SDK, through the message wParam parameter identification.