Use of SetCaption() about govcl HOT 4 CLOSED

package main

import (
	"github.com/ying32/govcl/vcl"
)

var (
	mainForm *vcl.TForm
)

// ControlType is the variable used as an enum
type ControlType int

const (
	Label ControlType = 1 + iota
	Button
)

type Form struct {
	*vcl.TForm
}

func main() {
	vcl.Application.Initialize()
	mainForm = vcl.Application.CreateForm()
	mainForm.SetCaption("Hello to you!!")
	mainForm.ScreenCenter()
	AddLabel(mainForm, mainForm, 10, 10, 100, 22, "A functional label!")
	AddButton(mainForm, mainForm, 10, 40, 40, 20, "Click Me!")
	vcl.Application.Run()
}

// AddLabel adds a new Label
func AddLabel(owner vcl.IComponent, parent vcl.IWinControl, left int32, top int32, width int32, height int32, caption string) *vcl.TLabel {
	label := CreateControl(owner, Label)
	label.SetParent(parent)
	label.SetBounds(left, top, width, height)
	label.SetCaption(caption)
	return label.(*vcl.TLabel)
}

// AddButton adds a new button
func AddButton(owner vcl.IComponent, parent vcl.IWinControl, left int32, top int32, width int32, height int32, caption string) *vcl.TButton {
	button := CreateControl(owner, Button)
	button.SetParent(parent)
	button.SetBounds(left, top, width, height)
	button.SetCaption(caption)
	return button.(*vcl.TButton)
}

// CreateControl is a "Generic" factory method for Control creation
func CreateControl(owner vcl.IComponent, controlType ControlType) vcl.IControl {
	switch controlType {
	case Label:
		return vcl.NewLabel(owner)
	case Button:
		return vcl.NewButton(owner)
	default:
		return nil
	}
}