根据参数设置构造函数的成员数据类型

Question

我有一个具有枚举值作为参数的类。它具有m_ConsistencyErrors 成员std::set。我想根据枚举参数的值将该成员的类型设置为构造。

。

如果TestType值为MSG123_CONSISTENCY_TEST，我希望M_ConsistencyErrors为std::set<EnMsg123Param>

类型

如果TestType值为MSG5_CONSISTENCY_TEST，我希望M_ConsistencyErrors为std::set<EnMsg5Param>

有一种干净的方法可以实现这一目标，或者我应该找到另一种解决方案。

class CMsgConsistencyTest // : public CTestBase  // left out for simplicity
{
    enum EnTests
    {
        MSG123_CONSISTENCY_TEST,
        MSG5_CONSISTENCY_TEST,
    };
    enum EnMsg123Param
    {
        Msg123_1,
        Msg123_2
    };
    enum EnMsg5Param
    {
        Msg5_1,
        Msg5_2
    };
public:
    CMsgConsistencyTest(const EnTests TestType) //  : CTestBase(TestType)  // left out for simplicity
    {
        if (TestType == MSG123_CONSISTENCY_TEST)
        {
            ParameterType = EnMsg123Param;  // pseudo code
        }
        else if (TestType == MSG5_CONSISTENCY_TEST)
        {
            ParameterType = EnMsg5Param;  // pseudo code
        }
    }
private:
    template<typename ParameterType>
    std::set<ParameterType> m_ConsistencyErrors;
};

Answer 1

您无法执行此操作， parametertype 必须在使用 cmsgconsistencyTest 以及其成员访问m_ConsistencyErrors

对于该 cmsgconsistencyTest 可以是模板类，示例

#include <set>
enum EnMsg123Param
{
  Msg123_1,
  Msg123_2,
};
enum EnMsg5Param
{
  Msg5_1,
  Msg5_2,
  Msg5_3,
};
template<typename ParameterType>
class CMsgConsistencyTest // : public CTestBase  // left out for simplicity
{
  public:
    // ...
  private:
    std::set<ParameterType> m_ConsistencyErrors;
};
// and for instance
CMsgConsistencyTest<EnMsg123Param> A;
CMsgConsistencyTest<EnMsg5Param> B;

否则，您可能必须做一些丑陋，灾难性的和"非C "的事情：

   CMsgConsistencyTest(const EnTests TestType) //  : CTestBase(TestType)  // left out for simplicity
    {
        if (TestType == MSG123_CONSISTENCY_TEST)
        {
            m_ConsistencyErrors = new set<EnMsg123Param>;
        }
        else if (TestType == MSG5_CONSISTENCY_TEST)
        {
            m_ConsistencyErrors = new set<EnMsg5Param>;
        }
        // else ?
        // probably need to save TestType etc
    }
private:
    void * m_ConsistencyErrors;