It is bit too late after you posted your question but I saw it only now. You need to add the include path to the project settings. Go to Project->Properties->Configuration Properties->VC++ Directories. Here you need to select Include Directories and enter path to the Include folder in the Astra SDK. For example, I have entered this path: F:\Cameras\3D Cameras\Pattern Projection Type\Orbbec\AstraSDK-v2.0.16-e6b4f7afb2-20190516T030922Z-vs2015-win32\include
Be sure to select the correct project configuration in the above dialog box (property pages).
Hope this helps you.