要将 `std::map<std::string, std::map<std::string, std::map<std::string, std::map<std::string, std::map<std::string, std::vector<CXHFCODE>>>>>>` 替换为使用 `CString` 作为键的结构,同时保持嵌套层次不变,需要对每一层的 `std::map<std::string, ...>` 进行替换。
具体做法是将所有以 `std::string` 为键的 `std::map` 替换为以 `CString` 为键的 `std::map`。由于 `CString` 是 MFC 中的字符串类,其重载了比较运算符(如 `<`),因此可以直接用于 `std::map` 的键类型而无需额外提供比较函数。
以下是替换前后的结构对比:
替换前:
```cpp
std::map<std::string, std::map<std::string, std::map<std::string, std::map<std::string, std::map<std::string, std::vector<CXHFCODE>>>>>>
```
替换后:
```cpp
std::map<CString, std::map<CString, std::map<CString, std::map<CString, std::map<CString, std::vector<CXHFCODE>>>>>>
```
遍历该结构时,需显式声明迭代器类型并使用 `CString` 类型的键进行访问:
```cpp
typedef std::map<CString, std::map<CString, std::map<CString, std::map<CString, std::map<CString, std::vector<CXHFCODE>>>>>> NestedCStringMap;
NestedCStringMap regions_;
for (NestedCStringMap::iterator itProvince = regions_.begin(); itProvince != regions_.end(); ++itProvince) {
const CString& provinceKey = itProvince->first;
const std::map<CString, std::map<CString, std::map<CString, std::map<CString, std::vector<CXHFCODE>>>>>& cityMap = itProvince->second;
for (std::map<CString, std::map<CString, std::map<CString, std::map<CString, std::vector<CXHFCODE>>>>>::iterator itCity = cityMap.begin(); itCity != cityMap.end(); ++itCity) {
const CString& cityKey = itCity->first;
const std::map<CString, std::map<CString, std::map<CString, std::vector<CXHFCODE>>>>& districtMap = itCity->second;
for (std::map<CString, std::map<CString, std::map<CString, std::vector<CXHFCODE>>>>::iterator itDistrict = districtMap.begin(); itDistrict != districtMap.end(); ++itDistrict) {
const CString& districtKey = itDistrict->first;
const std::map<CString, std::map<CString, std::vector<CXHFCODE>>>& townMap = itDistrict->second;
for (std::map<CString, std::map<CString, std::vector<CXHFCODE>>>::iterator itTown = townMap.begin(); itTown != townMap.end(); ++itTown) {
const CString& townKey = itTown->first;
const std::map<CString, std::vector<CXHFCODE>>& villageMap = itTown->second;
for (std::map<CString, std::vector<CXHFCODE>>::iterator itVillage = villageMap.begin(); itVillage != villageMap.end(); ++itVillage) {
const CString& villageKey = itVillage->first;
const std::vector<CXHFCODE>& codes = itVillage->second;
for (const CXHFCODE& code : codes) {
// 执行 SQL 插入操作
}
}
}
}
}
}
```
上述代码通过逐层定义迭代器和引用类型,确保在不使用 `auto` 的情况下正确访问每层数据[^3]。此方法保留了原始结构的嵌套逻辑,并利用 `CString` 提供的比较语义来保证 `std::map` 正常运行[^4]。