Question

I’m using Visual Studio 2008 Professional in C++ with Windows Form, I have a class that I have to pass to the other Form, so here is what I’m doing

//FirstFile.cpp

Usuario user;
user.usuario = "test";
user.senha = "stackoverflow";
ChooseService cs(user);     
cs.ShowDialog();

//SecondFile.cpp

public ref class ChooseService : public System::Windows::Forms::Form
    {
    public:

        Usuario* usuario;


        ChooseService(Usuario user)
        {


            usuario = user;         
            //I need to cast the Usuario into Usuario*, so I can use it in the class
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }
        /...

as I said in my comment, I need to cast “Usuario” into “Usuario*” so I can access in the class using “this”, by the way I can’t make this

Usuario usuario;

instead of pointer, because windows forms doesn’t allow you, you have to use pointer. so how do I do this? is there any trick?
I hope I was clear enough, Thanks!

Answer 1

Getting the pointer from an object is easy:

Usuario user;
Usuario* pUser = &user;

But it might render the pointer invalid, because user is in automatic storage and might be destroyed before you’re done using pUser.

I suggest you allocate user dynamically and modify the constructor of ChooseService to take a pointer:

Usuario* user = new Usuario;
user->usuario = "test";
user->senha = "stackoverflow";
ChooseService cs(user);


//...

ChooseService(Usuario* user) {...}

In your particular case, your variant would work because both objects have the same lifetime, but it’s dangerous in the long run.