c++ - 通过访问容器的父级来使用 sigc::mem_fun

Question

我正在尝试用 Gtkmm3 制作一个简单的软件。
我想要一个里面有网格的窗口。单击该网格内的按钮时，应触发窗口的一种方法以删除当前网格并将其替换为另一个网格。
我可以使用这样的网格方法:

button.signal_clicked().connect(sigc::mem_fun(*this, &MyGrid::someMethod));

“这个”是 MyGrid。
我想做这样的事情:

button.signal_clicked().connect(sigc::mem_fun(*this->get_parent(), &MyWindow::someMethod));

其中 this->get_parent() 将是 MyWindow 的一个实例
我的.h:

#ifndef MINIPROJECT_GUI_H
#define MINIPROJECT_GUI_H

#include <gtkmm/button.h>
#include <gtkmm/window.h>
#include <gtkmm/grid.h>
#include <iostream>
#include <string>
#include <map>
#include <vector>
#include <gtkmm/label.h>


class WelcomeGrid: public Gtk::Grid
{
    Gtk::Label message;
    Gtk::Button nextButton; // This button should be connected to Fenetre::infoView()
public:
    WelcomeGrid();
    void display();

};


class InfoGrid : public Gtk::Grid
{
    Gtk::Button button2;// This button should be connected to Fenetre::welcomeView()
    Gtk::Label label2;
public:
    InfoGrid();
    void display();
};


class Fenetre : public Gtk::Window
{

public:
    Fenetre();
    virtual ~Fenetre(); // Setup window

    void welcomeView();

protected:
    //Member widgets:
    WelcomeGrid welcome;
    InfoGrid info;
    void infoView(); // Remove the current grid from the window and replace it by infoGrid
    void welcomeView(); // Remove the current grid from the window and replace it by WelcomeGrid

};


#endif //MINIPROJECT_GUI_H

我的 .cpp :

#include "GUI.h"

Fenetre::Fenetre()
{
    // Sets the border width of the window.
    set_border_width(10);
    this->add(welcome);
}

Fenetre::~Fenetre()
{
}

void Fenetre::welcomeView() {
    this->remove();
    this->add(welcome);
}

void Fenetre::infoView() {
    this->remove();
    this->add(info);
}


InfoGrid::InfoGrid() {
    button2.set_label("Hello.");
    button2.signal_clicked().connect(sigc::mem_fun(*this,
                                                   &InfoGrid::display));

    label2.set_label("Welcome on the Vampire creation interface.");
    this->attach(label2, 0, 0, 1, 1);
    this->attach(button2,1,1,1,1);
    button2.show();
    this->show_all();
}



WelcomeGrid::WelcomeGrid() {
    nextButton.set_label("Create new character.");
    auto a = this->get_parent();
    nextButton.signal_clicked().connect(sigc::mem_fun(*this,
                                                   &WelcomeGrid::display));

    message.set_label("Welcome on the Vampire creation interface.");
    this->attach(message, 0, 0, 1, 1);
    this->attach(nextButton,1,1,1,1);
    // This packs the button into the Window (a container);
    this->show_all();
}

void WelcomeGrid::display() {
    auto a = this->get_parent();
    std::cout << typeid(a).name();
}

void InfoGrid::display() {
    std::cout << "coucou";
}

Answer 1

没有任何代码，很难知道您到底在寻找什么。我会这样做:我会在网格内保留对父窗口的引用。例如:

#include <iostream>
#include <memory>
#include <sstream>

#include <gtkmm.h>

class MyWindow : public Gtk::Window
{

public:

    MyWindow()
    : m_grid{std::make_unique<MyGrid>(*this, m_count)}
    {
        add(*m_grid);
    }

    // This is called when the grid's button is pressed:
    void ReplaceGrid()
    {
        ++m_count; 
        
        // Remove the grid from the window:
        remove();

        // Destroy current grid:
        m_grid = nullptr;

        // Create a new grid:
        m_grid = std::make_unique<MyGrid>(*this, m_count);

        // Add it to the window:
        add(*m_grid);

        show_all();
    }

private:

    class MyGrid : public Gtk::Grid
    {
    
    public:
    
        MyGrid(MyWindow& p_parent, int p_count)
        : m_parent{p_parent}
        {
            // Create button:
            std::ostringstream ss;
            ss << "Replace me #" << p_count;
            m_replaceButton = Gtk::Button(ss.str());
    
            // Attach it to the grid:
            attach(m_replaceButton, 0, 0, 1, 1);
    
            // Connect replacement signal, using the parent window:
            m_replaceButton.signal_clicked().connect([this]()
                                                     {
                                                         // Call the parent (the window):
                                                         m_parent.ReplaceGrid();
                                                     });
        }

        ~MyGrid()
        {
            std::cout << "Grid destroyed" << std::endl;
        }
    
    private:
    
        Gtk::Button m_replaceButton;

        // Keep a reference to the parent window in the grid:
        MyWindow&   m_parent;
    };

    int                     m_count = 0;
    std::unique_ptr<MyGrid> m_grid;
};

int main(int argc, char *argv[]) 
{
    auto app = Gtk::Application::create(argc, argv, "so.question.q64594709");
    MyWindow w;

    w.show_all();
    
    return app->run(w);
}

如果您运行此代码，您将看到一个带有一个包含一个按钮的网格的窗口。每当您单击按钮时，窗口:

更新计数器

破坏当前网格

使用更新后的计数器值

创建一个新网格

您将在新网格的按钮标签上看到更新的计数器值。在终端中，grids 析构函数将打印一条消息，证明 grids 确实被切换了。
请注意，我在这里使用了 lambdas 来清理语法。我建议你也这样做。如果你真的想用 sigc::men_fun ，您可以将 lambda 的内容封装到 MyGrid::someMethod您在问题中提到的方法。
另请注意，网格是窗口的私有(private)嵌套类(没有其他人需要知道......)。
使用 GCC 编译:

g++ main.cpp -o example.out `pkg-config gtkmm-3.0 --cflags --libs`