Message Handling

Binding message handlers

The preferred way to handle window messages is with the neo::WindowBase::Bind() mechanism. This mean a message handler is attached to the messages that require it. The message handler can have any name, and can be static or a member function, even a functor. But it must have return type void and take a neo::Message& as parameter. Subclasses of message are also valid choices for parameters.

using namespace neo;

class LoginDialog : public WindowModal
{
public:
    NameDialog(LoginController* pLogin)
    {
        Size s(300, 100);
    
        login = pLogin;
        // non resizable dialog
        Create(WindowParam()
            .Text("Enter your name and password")
            .Style(WS_OVERLAPPED|WS_SYSMENU|WS_CAPTION)
            .InnerSize(s));
        
        textName = TextBox(*this, Rect(5, 5, s.cx - 10, 25));
        textPassword = TextBox(*this, Rect(5, 35, s.cx - 10, 25), ControlParam().AddStyle(ES_PASSWORD));
        Button buttonOk = Button(*this, "Ok", Rect(s.cx - 210, s.cy - 35, 100, 25));
        Button buttonCancel = Button(*this, "Ok", Rect(s.cx - 105, s.cy - 35, 100, 25));
        
        Bind(WM_CLOSE, &LoginDialog::DialogCancel, this);
        Bind(ButtonMessageId(buttonOk), &LoginDialog::DialogOk, this);
        Bind(ButtonMessageId(buttonCancel), &LoginDialog::DialogCancel, this);
    }
    
    void DialogOk(Message& m)
    {
        if(login->DoLogin(textName.GetText(), textPassword.GetText()))
            EndModal(IDOK);
    }
    
    void DialogCancel(Message& m)
    {
        EndModal(IDCANCEL);
    }
private:
    LoginController* login;
    TextBox textName;
    TextBox textPassword;
};

Old school

The above code example works and looks pretty clean. But for those who like direct access to the windows messages, the old school neo::WindowBase::WndProc() is also available as a virtual function.

using namespace neo;

class LoginDialog : public WindowModal
{
public:
    static const int BUTTON_OK = 100;
    static const int BUTTON_CANCEL = 101;

    NameDialog(LoginController* pLogin)
    {
        Size s(300, 100);
    
        login = pLogin;
        // non resizable dialog
        Create(WindowParam()
            .Text("Enter your name and password")
            .Style(WS_OVERLAPPED|WS_SYSMENU|WS_CAPTION)
            .InnerSize(s));
        
        textName = TextBox(*this, Rect(5, 5, s.cx - 10, 25));
        textPassword = TextBox(*this, Rect(5, 35, s.cx - 10, 25), ControlParam().AddStyle(ES_PASSWORD));
        Button buttonOk = Button(*this, "Ok", Rect(s.cx - 210, s.cy - 35, 100, 25), ControlParam().Id(BUTTON_OK));
        Button buttonCancel = Button(*this, "Ok", Rect(s.cx - 105, s.cy - 35, 100, 25), ControlParam().Id(BUTTON_CANCEL));
    }
    
    virtual LRESULT WndProc(HWND window, UINT message, WPARAM wp, LPARAM lp) override
    {
        switch(message)
        {
        case WM_CLOSE:
            EndModal(IDCANCEL);
            break;
        case WM_COMMAND:
            if(HIWORD(wp) == BN_CLICKED)
            {
                switch(LOWORD(wp))
                {
                case BUTTON_OK:
                    if(login->DoLogin(textName.GetText(), textPassword.GetText()))
                        EndModal(IDOK);
                    break;
                case BUTTON_CANCEL;
                    EndModal(IDCANCEL);
                    break;
                }
            }
        }
        
        return WindowModal::WndProc(window, message, wp, lp);
    }
private:
    LoginController* login;
    TextBox textName;
    TextBox textPassword;
};

If you are using C++11, you can also bind lambda expressions.

using namespace neo;

class BindLambda : public Window
{
    BindLambda()
    {
        Create(WindowParam());
        
        Button button = Button(*this, L"Increase x", 0, 0, 0, 100, 25);
        
        auto incr = [this](msgCommand&)
        {
            ++x;
        }
        
        Bind(ButtonMessageId(button), incr);
    }
    
    int x;
};