ListBox编程两例

　　1。 为ListBox添加水平方向的滚动条

　　SendMessage (ListBox1-Handle,LB_SETHORIZONTALEXTENT,ListBox1-Width + 32,0) ;

　　2。 为Listbox添加图标

　　首先需要设置Listbox的Style属性为lbOwnerDrawVariable;

const margin = 2 ; // Margin around each bitmap
//---------------------------------------------------------------------------
void __fastcall TForm1::ListBox1MeasureItem(TWinControl *Control, int Index,
int &Height)
{
Height = ImageList1-Height + margin * 2 ;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ListBox1DrawItem(TWinControl *Control, int Index,
TRect &Rect, TOwnerDrawState State)
{
// 填充背景.
ListBox1-Canvas-FillRect (Rect) ;
// 画出图像.
ImageList1-Draw (ListBox1-Canvas, Rect.Left + margin, Rect.Top + margin, Index) ;
// 画出文字.
String text = ListBox1-Items-Strings [Index] ;
// Center the text vertically in relation to the bitmap.
int off = (Rect.Bottom - Rect.Top - ListBox1-Canvas-TextHeight (text)) / 2 ;
ListBox1-Canvas-TextOut (Rect.Left + ImageList1-Width + 2 * margin,
Rect.Top + off,text) ;
}