DLL返回自定义结构的数组

 

Txml.h 自定义了结构体 与对应的类

 

typedef enum {
    CHOICE_STYLE_OTHER,
    CHOICE_STYLE_TEXT,
    CHOICE_STYLE_IMG

}ChoiceStyle;

typedef struct {
    char CIID;
    ChoiceStyle EnumChoiceStyle;        
    char ChoicePath[MAXPATH];    
    char ChoiceContent[MAXQCONTENT];

}ChoiceItem;

typedef struct {
    char QID[MAXID];     
    char QContent[MAXQCONTENT];
    char ContentAudio[MAXPATH];
    ChoiceItem ChoiceItemA;            
    ChoiceItem ChoiceItemB;            
    ChoiceItem ChoiceItemC;            
    ChoiceItem ChoiceItemD;        
    char Answer[1];

}QuestionItem;
 

class Txml
{
public:
 Txml();
 ~Txml();
private:
 
 QuestionItem QuestionItemArray[MAXARRAYSIZE];
 int QuestionItemArraySize;
 
public:
 int LoadXml(const char *XmlFilePath);
 QuestionItem QueryQuestionbyID(char *ID);
 QuestionItem* QueryQuestionArray();
};

 

Txml.cpp

 

int Txml::LoadXml(const char *XmlFilePath)
{
//加载XmlFilePath
//将其读到QuestionItemArray中
}

 

QuestionItem* Txml:: QueryQuestionArray()//注意声明的返回的是自定义结构的指针
{
     //注意返回的是数组名（地址）
     //此前犯错，返回第一个元素QuestionIte[0]
    return QuestionItemArray;
}

 

 

DLL实现如下：

MyDLL.h

 

extern "C" __declspec(dllexport) void  *FillQuestionItem(const char* FileName);

 

MyDLL.cpp

 

void   *FillQuestionItem(const char* FileName)
{
    QuestionItem *QuestionItemP;

    Txml *objTxml= new Txml();
    objTxml->LoadXml(FileName);
    QuestionItemP = (objTxml->QueryQuestionArray());    
    return QuestionItemP;
    
}

 

 

应用层调用的核心部分：

 

//加载测试配置文件
void CMyExam2Dlg::LoadTXml(const char *szXmlFileToSave)
{
    typedef void*  (*pFillQuestionItem)(const char* FileName);


    HINSTANCE HDLL;                   //定义句柄
    
    pFillQuestionItem FillQuestionItem;    

    HDLL=LoadLibrary(MyDLLPath);   

    //加载动态链接库FIRSTDll.dll文件,注意指明FIRSTDLL的地址哦
    if(HDLL==NULL) 
        ::OutputDebugString("cannot find the dll file");

    int my_int = *(int*)GetProcAddress(HDLL, "nMyDLL");
    
    FillQuestionItem=(pFillQuestionItem)GetProcAddress(HDLL,"FillQuestionItem"); 

    QuestionItem *QuestionItemP;
    QuestionItem QuestionItemP1[10];
    QuestionItemP=(QuestionItem*)FillQuestionItem(szXmlFileToSave );


    memcpy(QuestionItemP1, QuestionItemP, sizeof(QuestionItem) * 10);    

    FreeLibrary(HDLL);//卸载MyDll.dll文件；
}

 

 

自定义的xml结构

 

<?xml version="1.0" encoding="gb2312" ?> 
- <resource id="20110512171112">
- <Question id="0">
  <Content>1</Content> 
  <ContentAudio>.\01.mp3</ContentAudio> 
  <Choice STYLE="TEXT">a</Choice> 
  <Choice STYLE="TEXT">b</Choice> 
  <Choice STYLE="TEXT">c</Choice> 
  <Choice STYLE="TEXT">d</Choice> 
  <Answer>B</Answer> 
  </Question>
- <Question id="1">
  <Content>2</Content> 
  <ContentAudio>.\02.mp3</ContentAudio> 
  <Choice STYLE="TEXT">2</Choice> 
  <Choice STYLE="TEXT">2</Choice> 
  <Choice STYLE="TEXT">2</Choice> 
  <Choice STYLE="TEXT">2</Choice> 
  <Answer>B</Answer> 
  </Question>
......
repeat more 8 times
</resource>

 

 

PS:

感谢师傅指导.