In WinUser.h:
#define ES_LEFT 0x0000L
#define ES_CENTER 0x0001L
#define ES_RIGHT 0x0002L
so you can do
void TextBox::Alignment(ALIGNMENT Alignment)
{
int style = ES_LEFT; // default to left alignment
switch (Alignment)
{
case ALIGNMENT::Center:
style = ES_CENTER;
break;
case ALIGNMENT::Right:
style = ES_RIGHT;
break;
}
SetWindowLongPtr(m_hWnd, GWL_STYLE, GetWindowLongPtr(m_hWnd, GWL_STYLE) & ~(ES_CENTER|ES_RIGHT) | style);
InvalidateRect(m_hWnd, NULL, TRUE);
UpdateWindow(m_hWnd);
};