如何使用模板成员函数作为另一个模板成员函数的参数？

Question

所以我正在试验模板，可能我在某个地方遇到了语法问题。我正在尝试编写一个 class，它采用所选项目的向量，将它们的属性转换为布尔数组，然后生成代表整个选择状态的对象>该对象被发送到 UI 查看并显示在带有三态复选框的上下文菜单上。我知道如何以漫长而艰难的方式编写它，但我想避免代码重复，所以我决定使用模板。问题是我不能将一个成员函数传递给另一个成员函数。我收到编译错误 C3867 非标准语法；使用“&”创建指向成员的指针。

首先：抱歉，如果是重复的。第二：对不起，这个长例子，但我不知道我的错误在哪里。

#include <array>
#include <vector>
#include "Item.h"

enum class CheckState {unchecked, checked, partially_checked}; //the state of the context menu checkboxes

struct CheckBoxModels    //this is the final product we want to get
{                    
    std::array<CheckState, 10> general;
    std::array<CheckState, 6> surface;
    std::array<CheckState, 7> other;
};

class CheckModelGenerator{          //this class has to generate the chechBoxModel by taking a vector of pointers to the selected Items;

    std::array<bool, 10> getGeneralStatus(const Item& item); //each of these knows how to get a specific list of properties from an item 
    std::array<bool, 6> getSurfaceStatus(const Item& item); //and represent it with boolean
    std::array<bool, 7> getSomeOtherStatus(const Item& item);//depending on whether they exist or not;

    template<int Size>                                      //using this to call ANY of the functions above
    using getAnyStatus = std::array<bool, Size>(CheckModelGenerator::*) (const Item& item);

    template<int size> //a member function that converts the bool arrays to CheckState arrays, by iterrating trough the selected items
    std::array<CheckState, size> getCheckStateFromAnyStatus(const std::vector<Item*>& selectedItems, getAnyStatus<size> getStatus);

public:

    CheckBoxModels getAllCheckBoxModels(std::vector<Item*>& selectedItems) // this here creates the final product;
    {
        CheckBoxModels models;
        models.general = getCheckStateFromAnyStatus(selectedItems, getGeneralStatus); //I'm having problem actually calling those template functions!
        models.surface = getCheckStateFromAnyStatus(selectedItems, getSurfaceStatus);
        models.other = getCheckStateFromAnyStatus(selectedItems, getSomeOtherStatus);

        return models;
    }

};

Answer 1

好吧，您确实缺少 & 并且必须在名称前加上 class 名称。试试这个：

models.general = getCheckStateFromAnyStatus(selectedItems, &CheckModelGenerator::getGeneralStatus);
models.surface = getCheckStateFromAnyStatus(selectedItems, &CheckModelGenerator::getSurfaceStatus);
models.other = getCheckStateFromAnyStatus(selectedItems, &CheckModelGenerator::getSomeOtherStatus);

如何使用模板成员函数作为另一个模板成员函数的参数？

How to use a template member function as an argument to another template member function?

c++

templates

member-functions