VS2019：致命错误 C1083 无法打开头文件：'opencv.hpp'

Question

It is all fine when I was writing the code, that is, when I included the header file "opencv2/opencv.hpp",
and VS2019 can indeed "see" it,
in other words, I can use the class that is in the opencv.hpp, but only when I complied the project,c1083 occurred

before i added the function DrawLine(),i compiled for times,with no err.and then i added the function DrawLine(..),error occurred

this is the total source code

ah
a.cpp

//a.h
#include<opencv2\opencv.hpp>

using namespace cv;

class Canvas{
    Mat mat_canvas;

    void Init(){
        mat_canvas.create(1024,1024,CV_32FC3);
    }

    void DrawLine(float ax,float ay,float bx,float by);
}

//a.cpp
#include"a.h"

void Canvas::DrawLine(float ax,float ay,float bx,float by){
    cv::line(this->mat_canvas,Point2f(ax,ax),Point2f(bx,by),Scalar(1,1,1));
}

error msg was:

fatal error C1083 Cannot open header file: 'opencv.hpp': no such file or dir

i know i can create a new solution and move my old solution to it,but it takes time,and i can't actually know whether this issue will happen again in my new solution

Any answer will be helpful

Answer 1

Actually there are most of the time possibility of missing "Additional include directory path" or wrongly setup.

Where to find in Visual Studio:

To set this compiler option in the Visual Studio development environment

1. Open the project's Property Pages dialog box. For details, see Set C++ compiler and build properties in Visual Studio.
2. Select the Configuration Properties > C/C++ > General property page.
3. Modify the Additional Include Directories property.

Visual Studio 2019 C++ Project configuration

Example project setup is described in below link: Example setup