这个控件里面其实包括了之前所有的控件,水平滚动,垂直滚动,列表框,这个组合框是拼凑起来的.想慢慢地,一步步摆脱系统控件,自己写控件其实也挺有意思的. -This controls which actually includes all of the controls before, horizontal scrolling, vertical scrolling list box, the combo box is pieced together. Think slowly, step by s