//----------------------------------------------------------------------------//
void __fastcall TForm1::Button1Click(TObject *Sender)
{
  Label1->Caption="0123456789abcABCWIMwim";
  AnsiString as;
  for(int i=0;iCaption.Length();i  )
  {
    as.printf("char[%d] StartXPos=%d\n",i,
       Label1->Canvas->TextWidth(Label1->Caption.SubString(1,i)));
    ListBox1->Items->Add(as);
  }
}
//----------------------------------------------------------------------------//
void __fastcall TForm1::Label1MouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
  for(int i=0;iCaption.Length();i  )
  {
    if(X>=Label1->Canvas->TextWidth(Label1->Caption.SubString(1,i))
    && X<=Label1->Canvas->TextWidth(Label1->Caption.SubString(1,i 1)))
    {
      Label2->Caption="第" IntToStr(i) "個字";
      return;
    }
  }
  Label2->Caption="不知道是第幾個字";
}
//----------------------------------------------------------------------------//