LNK 2019 "Unresolved External Symbol"错误 (C++ OpenGL)

我对C++还比较陌生，在文件中创建类时遇到了一些问题。我试图从一个单独的类Shader中调用一个构造函数，并在该类中使用一个方法。然而，每当我试图构建解决方案时，我都会收到以下错误：

Error   2   error LNK2019: unresolved external symbol "public: void __thiscall Shader::Use(void)" (?Use@Shader@@QAEXXZ) referenced in function _main    
Error   1   error LNK2019: unresolved external symbol "public: __thiscall Shader::Shader(char const *,char const *)" (??0Shader@@QAE@PBD0@Z) referenced in function _main

我知道Project Properties Linker或渲染系统没有什么问题，因为我以前用我当前的配置渲染过东西，所以我认为这一定与代码有关，但我无法弄清楚：

main.cpp

#include <iostream>
// GLEW
#define GLEW_STATIC
#include <GL/glew.h>
// GLFW
#include <GLFW/glfw3.h>
// Other includes
#include "Shader.h"
int main ()
{
(... Window Setup ...)

// Build and compile shader program
Shader shaders ("shader.vs", "shader.frag");

(... Set up vertex data (and buffer(s)) and attribute pointers ...)
// Game loop
while(!glfwWindowShouldClose (window))
{
    glfwPollEvents ();
    ourShader.Use ();
(... Draw triangle ...)
    glfwSwapBuffers (window);
}
(... De-allocate all resources ...)
(... Terminate window ...)
return 0;
}

Shader.h

#ifndef SHADER_H
#define SHADER_H
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <GL/glew.h>
class Shader
{
public:
GLuint Program;
Shader(const GLchar* vertexPath, const GLchar* fragmentPath);
void Use ();
};
#endif

Shader.cpp

#ifndef SHADER_H
#define SHADER_H
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <GL/glew.h>
#include "Shader.h"
class Shader
{
public:
GLuint Program;
Shader::Shader(const GLchar* vertexPath, const GLchar* fragmentPath)
{
    (... 1. Retrieve the vertex/fragment source code from filePath ...)
    (... 2. Compile shaders ...)
    (... 3. Link shader program ...)
    (... 4. Delete shaders after usage ...)
}
void Shader::Use ()
{
    (... Use current shader program ...)
}
};
#endif

如有任何帮助，我们将不胜感激。如果需要更多的代码，我可以提供。提前感谢！