unit1.pas

delphi6.0 的控件示例

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    ComboBox1: TComboBox;
    ListBox1: TListBox;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure ListBox1KeyPress(Sender: TObject; var Key: Char);
  private
    FSearchStr: string;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  FSearchStr := '';
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i:integer;
begin
  Listbox1.Items.Clear;       //可删除，防止重复按下 [Button1]
  ComboBox1.Items.Clear;      //可删除，防止重复按下 [Button1]
  for i:=ord('a') to ord('z') do
  begin
    Listbox1.Items.Add(chr(i-1)+chr(i)+chr(i+1));
    ComboBox1.Items.Add(chr(i-1)+chr(i)+chr(i+1));
  end;
end;

procedure TForm1.ListBox1KeyPress(Sender: TObject; var Key: Char);
var
  i: Integer;
begin
  Case Key of
    #27: Begin
           // Escape key, clear search string
           FSearchStr := EmptyStr;
         End; { Case Esc }
    #8 : Begin
           // backspace, erase last key from search string
           If Length(FSearchStr) > 0 Then
             Delete( FSearchStr, Length( FSearchStr), 1 );
         End; { Case backspace }
    Else
      FSearchStr:= FSearchStr + Key;
  End; { Case }
  If Length(FSearchStr) > 0 then
    if Sender is TListbox then Begin
      i:= SendMessage( TListbox(Sender).handle, LB_FINDSTRING,
                       TListbox(Sender).ItemIndex-1, longint(@FSearchStr[1]));
      If i <> LB_ERR Then
        TListbox(Sender).ItemIndex := i;
    end
    else
      if Sender is TCombobox then begin
        i:= SendMessage( TCombobox(Sender).handle, CB_FINDSTRING,
                         TCombobox(Sender).ItemIndex-1, longint(@FSearchStr[1]));
        If i <> LB_ERR Then
          TCombobox(Sender).ItemIndex := i;
      end;
  Key := #0;
end;

end.