C++ - 我可以传递子类作为参数而不是基类吗

发布于 2025-01-11 15:42:50 字数 1124 浏览 0 评论 0原文

我有这个：

class DATABASE_API MySQLConnection
{
}

然后是一个子类：

class DATABASE_API WorldDatabaseConnection : public MySQLConnection
{
}

然后我有这个：

class GameDatabase {
public:
    GameDatabase(PreparedStatement<MySQLConnection>* preparedStatement, GameDatabaseFlags gdf)
    {
        _gameObjectDatabaseFlag = gdf;
        _preparedStatement = preparedStatement;
    };
    GameDatabaseFlags _gameObjectDatabaseFlag;
protected:
    uint32_t versionId;
    virtual void MapGameDatabase(GameDatabaseContainer gameDatabaseContainer) = 0;
    PreparedStatement<MySQLConnection>* _preparedStatement;
};

当我尝试像这样初始化 GameDatabase 时：

PreparedStatement<WorldDatabaseConnection> * stmt = WorldDatabase.GetPreparedStatement(WORLD_SEL_GAMEOBJECTS_TEMPLATE);

auto gameDatabase = new GameDatabase(stmt,GAMEOBJECTS_DB);

我收到以下错误：

没有匹配的构造函数来初始化“GameDatabase”

这是为什么？我不能简单地使用子类WorldDatabaseConnection来代替基类MySQLConnection吗？

原文

I have this:

class DATABASE_API MySQLConnection
{
}

And then a child class:

class DATABASE_API WorldDatabaseConnection : public MySQLConnection
{
}

Then I have this:

class GameDatabase {
public:
    GameDatabase(PreparedStatement<MySQLConnection>* preparedStatement, GameDatabaseFlags gdf)
    {
        _gameObjectDatabaseFlag = gdf;
        _preparedStatement = preparedStatement;
    };
    GameDatabaseFlags _gameObjectDatabaseFlag;
protected:
    uint32_t versionId;
    virtual void MapGameDatabase(GameDatabaseContainer gameDatabaseContainer) = 0;
    PreparedStatement<MySQLConnection>* _preparedStatement;
};

When I try to initialize GameDatabase like so:

PreparedStatement<WorldDatabaseConnection> * stmt = WorldDatabase.GetPreparedStatement(WORLD_SEL_GAMEOBJECTS_TEMPLATE);

auto gameDatabase = new GameDatabase(stmt,GAMEOBJECTS_DB);

I get the following error: