VS低版本打開高版本常會出現的錯：
The build tools for v140 (Platform Toolset = 'v140') cannot be found. To build using the v140 build tools, please install v140 build tools. Alternatively, you may upgrade to the current Visual Studio tools by selecting the Project menu or right-click the solution, and then selecting "Upgrade Solution...".
解決方法：
項目--屬性--配置屬性--常規，找到 平台工具集 ，把v140改為v120（Visual Studio 2013 (v120))