C++ 没有合适的默认构造函数可用

Question

我有一些使用 C# 的经验，但 C++ 语法和程序构造会产生一些问题。我正在使用 Visual C++ 2008。首先为什么会出现此错误？:

1>......\Form1.h(104) : error C2512: 'Cargame::Car' : no appropriate default constructor available

其次，为什么这条线不可行？//System::Drawing::Color颜色;

error C3265: cannot declare a managed 'color' in an unmanaged 'Car'

Form1.h 包含:

namespace Cargame {
    using namespaces bla bla bla

    class Car;

    public ref class Form1 : public System::Windows::Forms::Form
    {
    public:
        Form1(void)
        {
            InitializeComponent();
        }
    Car* car;

        protected:
    ~Form1()
    {
        if (components)
        { delete components; }
    }

SOME MORE AUTOMATICALLY GENERATED CODE

    private: System::Void Form1_Load(System::Object^  sender, System::EventArgs^  e) {
                 panel1->BackColor = System::Drawing::Color::Green;
                 car = new Car();
                 //car->draw();
             }
    };
}

Car.h 的内容:

class Car
{
private:
        int speed;
        //System::Drawing::Color color;

public:
        Car();
};

Car.cpp 的内容

#include "stdafx.h"
#include "Car.h"
#include "Form1.h"
#include <math.h>

//extern TForm1 *Form1;

Car::Car()
{
        speed = 0;
}

void Car::draw()
{
//implementation
}

Answer 1

要解决错误 C2512，您需要添加:

#include "Car.h"

到 Form1.h。