Frame without borders and default controls. Sizers doesn't work

Question

I try to write small GUI programm for windows using wx and wxFrame. I have this code in ctor:

MainFrame::MainFrame(wxPoint pos)
    : wxFrame(NULL, wxID_ANY, wxT("Sample text"), pos,
              wxDefaultSize, wxBORDER_NONE | wxFRAME_NOTASKBAR)
{
    SetSize(wxSize(250, 100));
    CreateLayout();
}

And CreateLayout function:

void MainFrame::CreateLayout()
{
    wxBoxSizer* sizer = new wxBoxSizer(wxHORIZONTAL);

    sizer->Add(new wxStaticText(this, -1, "1000.56"), 0, wxLEFT|wxALIGN_CENTER_VERTICAL, 5);

    SetSizer(sizer);
}

As you can see, I want to align text to vertical center of the frame. But with this set of frame style flags sizers doesn't work! They work only if i set wxDEFAULT_FRAME_STYLE! But i need to have frame without borders and capture and close|minimize|maximize buttons, how can I get this work?

Answer 1

In the MainFrame constructor, move the call to SetSize() after the call to CreateLayout(). That's it.

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Normally, the call to Show() after creating the frame should make the above unnecessary, but it looks like in this case it doesn't (see the details below). Anyway, I think it makes sense to first set up all the sizers and controls inside the window, and then change the size to trigger a Layout(), just to be on the safe side.

This also means an alternative solution is to leave the call to SetSize() where it is, and force a layout by adding a call to Layout() at the very end of your CreateLayout(). But... I like being efficient (read: lazy); I'd go with the first solution.

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EDIT: I've found some information regarding why this happens.

For a wxFrame created with wxDEFAULT_FRAME_STYLE, the call to Show() ends up calling ::ShowWindow(), which triggers a WM_SIZE, which eventually triggers a Layout().

For a wxFrame created with wxBORDER_NONE, ::ShowWindow() doesn't seem to trigger a WM_SIZE, which is why the solutions above for forcing the call to Layout() are necessary.