func (e *Edit) TextSelection() (start, end int) {
	e.SendMessage(win.EM_GETSEL, uintptr(unsafe.Pointer(&start)), uintptr(unsafe.Pointer(&end)))
	return
}
TextSelection get Edit selection.
package wingui
import (
	"syscall"
	"unsafe"
	"github.com/lxn/win"
)
type Edit struct {
	WindowBase
	OnChanged func()
}
func (e *Edit) WndProc(msg uint32, wParam, lParam uintptr) uintptr {
	switch msg {
	case win.WM_COMMAND:
		switch win.HIWORD(uint32(wParam)) {
		case win.EN_CHANGE:
			if e.OnChanged != nil && lParam == uintptr(e.hwnd) {
				e.OnChanged()
			}
		}
	}
	return e.AsWindowBase().WndProc(msg, wParam, lParam)
}