Zhangjc,
TypeScript tooling will validate only files which are on script path of the main tsconfig.json. Could you please check whether a correct tsconfig.json, which contains your files is selected in your project properties? Right click on the project > Properties … > TypeScript and in group “tsconfig.json” please choose the main one for your project. Please let us know if it helped!
Best regards,
Piotr Tomiak