尝试使用DLL项目中的类时发生LNK2019错误[重复]

我正在为我的项目编写目录观察程序类。它在c++中的.dll类型项目。我使用Visual Studio 2013作为IDE。

我遵循了以下基本步骤:

1.创建了一个dll和c++语言类型的新项目

2.添加了类和dllExport类型声明

3.构建项目

4.创建控制台应用类型的新项目

5.向dll项目添加引用(两个项目位于不同的目录中)

6.指向附加包含文件中的头文件路径

但是 在编写了一些使用的代码之后。编译时,我收到以下错误

Error   1   error LNK2019: unresolved external symbol "public: __thiscall DirectoryWatcher::DirectoryWatcher(void)" (??0DirectoryWatcher@@QAE@XZ) referenced in function "void __cdecl `dynamic initializer for 'watcher''(void)" (??__Ewatcher@@YAXXZ) C:\Users\Karthik\documents\visual studio 2013\Projects\ConsoleApplication2\ConsoleApplication2\Source.obj   ConsoleApplication2*

但是Dll项目构建成功

一开始,我在指向析构函数时出错,但在头本身中编写了实现(空的只是大括号{})之后。该错误被指向构造函数的错误替换

她的头文件

#define _SCL_SECURE_NO_WARNINGS

#ifdef DIRECTORYWATCHER_EXPORTS
#define APITYPE __declspec(dllexport)
#else
#define APITYPE __declspec(dllimport)
#endif


#if defined(_WIN32) 
#define PLATFORM_WINDOWS
#elif __APPLE__
#define PLATFORM_MAC
#elif __linux
#define PLATFORM_LINUX
#endif
//-------------------------------------------
// Code Begins Here
//---------------------------------
#ifndef DIRECTORY_WATCHER_H
#define DIRECTORY_WATCHER_H

#define USE_DIRENT



//------------------------
// Includes
//--------------
#include<vector>
#include<iostream>
#include<fstream>
#include<string>
#include<sys\stat.h>
#include <tchar.h>
#include<map>

#ifdef PLATFORM_WINDOWS
#include<Windows.h>
#endif

#ifdef USE_BOOST
#include<boost/filesystem.hpp>
#include <boost/uuid/uuid.hpp>
#include <boost/uuid/uuid_io.hpp>
#include <boost/uuid/random_generator.hpp>
#include <boost/lexical_cast.hpp>
#endif

#ifdef USE_DIRENT
#include <dirent.h>
#endif

using namespace std;

//Meta File
template<typename T>
struct Meta
{
    string Name,Path;
    size_t GUID;
     float Size;
    int Type;

    // Can be anything like list of name or list of animation files or list of folder with a folder
     vector<T> MetaInfo;

};



//---------------------------------------------
// TYPE DEFS
//-------------------------------------

APITYPE typedef  hash<string> HashFunction;
APITYPE typedef Meta<string> FOLDER_META;


struct ChildrenTree
{
    vector<Meta<string>> Children;

};
struct DirectoryTree
{

    string ParentPath;
    //map<Children Name,Related Info>
    map<string, FOLDER_META> Child;

};

struct Changed_Data
{
    FOLDER_META Old;
    FOLDER_META New;
};

//------------------------------------
//operators
//------------------------------------


#ifdef USE_DIRENT
class DirectoryWatcher
{
    //-----------------Type Defs------------------------

    //typedef Meta<string> FOLDER_META;
public:
    //Varaibles
    FOLDER_META defaultMeta;
    Meta<DirectoryTree> TreeMeta;

    // Default Constructor
    DirectoryWatcher(void);


    ~DirectoryWatcher(void){}  // Eror at first pointed to the destructor which was solved by defining it here its self 

    // Obtains a list of files and folders in a directory
    APITYPE void GetList(const string&, vector<FOLDER_META>* ReturnValue ,FOLDER_META* ThisDireMeta);

    // Searches and Returns the pathto the file
    APITYPE bool FindFile(const string& Path
        ,const string& FileName // File Name
        , string* Ret //Path Returned 
        );

    //Update and check to see if a file as moved or added or changed 
    // Monitor(vector<FOLDER_META>* ChangedFiles,bool* FilesChanged -> return types); 
    APITYPE void Monitor(vector<Changed_Data>* ChangedFiles,bool* FilesChanged);

    // Creates a GUID for a file 
    APITYPE size_t CreateGUID(const string& fileName);

    //Export metadata
    APITYPE void ExportMeta(const string& Path,FOLDER_META meta);
    // Get the meta data
    APITYPE  void GetFolderMeta(const string& Path,Meta<string> * ReturnValue );

    //InitalizeMethod 
    // False if path invalid
    // true if path correct
    APITYPE bool Init(const string& Path //Path to the Project folder (The folder to watch)
        );

    APITYPE bool Init(const string& Path //Path to the Project folder (The folder to watch)
        ,vector<FOLDER_META> * Returnmetas);

    APITYPE void MakeDir(const string& path);


private:

    string Project_Path;
    DIR* dir = nullptr;
    DIR* MainDir = nullptr;
    struct dirent* ent = nullptr;
    DIR* tempDir = nullptr;
    DirectoryTree Tree;
    HashFunction hashFunc;

    //Dpeth Search 
    DirectoryTree UnVisited;


    //-------------------------------------
    // Windows Specifif cCode
    //---------------------------------
    HANDLE ChangeNotifications[2];
    TCHAR lpDrive[4];
    TCHAR lpFile[_MAX_FNAME];
    TCHAR lpExt[_MAX_EXT];
    DWORD Notifications; 



    // Private methods
    APITYPE long GetFolderSize( const string& Path);
    APITYPE bool CheckPathValid(const string& Path);

    APITYPE void RefreshFiles(vector<Changed_Data>* ChangedFiles,const string& path,bool OnlyThisFolder);
    APITYPE void RefreshTree(vector<Changed_Data>* ChangedFiles, const string& path);
    APITYPE void CreateTree(const string& Path );

    APITYPE void SaveTree();
    APITYPE void LoadTree();
    APITYPE bool AreChildEqual(const FOLDER_META& metaA,const FOLDER_META& metaB );
};
#endif

#endif // !DIRECTORY_WATCHER_H

*我省略了实现部分,因为它非常大,但这里只有构造函数*

DirectoryWatcher.cpp目录

  DirectoryWatcher::DirectoryWatcher(void)
    {

      Project_Path = "";
      dir = nullptr;
      MainDir = nullptr;
      ent = nullptr;
      tempDir = nullptr;
    }

测试应用程序

源.cpp

#include<DirectoryWatcher.h>


using namespace std;




DirectoryWatcher watcher;

// omitted part of code 
int main(int argv, char* argc) 
{
    string Path;
    cout << "enterPath";
    cin >> Path;

    bool ISCahnged;
    vector<FOLDER_META> metas,Returnvalues;
    vector<Changed_Data> changedDatas;
    watcher.Init(Path, &Returnvalues);

    while (true)
    {
        ISCahnged = false;
        watcher.Monitor(&changedDatas, &ISCahnged);

        if (ISCahnged)
        {
            for each (Changed_Data var in changedDatas)
            {
                OutChangedData(var);
            }
        }

    }

    return 0;
}

对于较小的代码,省略了几行

有人能帮忙解决这个问题吗

非常感谢。