unit1.pas

DELPHI经典程序

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    ComboBox1: TComboBox;
    Edit1: TEdit;
    Edit2: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Edit3: TEdit;
    Button1: TButton;
    Label4: TLabel;
    Label5: TLabel;
    procedure ComboBox1KeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure ComboBox1Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.ComboBox1KeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
 var
  AntiStart_1,AntiLength_1,AntiStart_2,AntiLength_2:Integer;
begin
  if Key =13 then
   Edit1.Text:=ComboBox1.SelText;

  AntiStart_1:=0;
  AntiLength_1:=ComboBox1.SelStart;
  AntiStart_2:=ComboBox1.SelStart+ComboBox1.SelLength+1;
  AntiLength_2:= Length(ComboBox1.Text)
                 -(ComboBox1.SelStart+ComboBox1.SelLength);

  Edit2.Text:=Copy(ComboBox1.Text,AntiStart_1,AntiLength_1)
             +Copy(ComboBox1.Text,AntiStart_2,AntiLength_2);
end;

procedure TForm1.ComboBox1Click(Sender: TObject);
begin
  Label4.Caption:='所选的是：'+#13
                   +ComboBox1.Items.Strings[ComboBox1.ItemIndex];
end;

procedure TForm1.Button1Click(Sender: TObject);
  var
   X,tmpIndex:Integer;
   ifExist:Boolean;
begin
  tmpIndex:=0;
  ifExist:=False;
  for X:=0 to ComboBox1.Items.Count-1 do
   if ComboBox1.Items.Strings[X]=Edit3.Text then
    begin
      tmpIndex:=X;
      ifExist:=True;
    end;
   
  if not ifExist then
   begin
     ComboBox1.Items.Add(Edit3.Text);
     ComboBox1.ItemIndex:=ComboBox1.Items.Count-1;
   end
  else
   begin
     ShowMessage('早就有资料啦！');
     ComboBox1.ItemIndex:=tmpIndex;
   end;
  ComboBox1.SetFocus;
end;

end.