cmediator.pas

delphi深度探索第二版随书光盘所附内容

{-----------------------------------------------------------------------------
 Unit Name: CMediator
 Author:    hubdog(陈省)
 Email:     [e-mail]
 Purpose:   演示Mediator模式的使用
 History:
            2003-6-20 创建本单元
-----------------------------------------------------------------------------}

unit CMediator;

interface

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

type
  TPerson = class(TObject)
  public
    Name: string;
    SafeFee: Double;
    PhoneFee: Double;
    Salary: Double;
  end;

  //调停者
  TMediator = class(TObject)
  public
    procedure ControlChanged(AControl: TControl); virtual;
  end;

  TFormMediator = class(TForm)
    lstPerson: TListBox;
    pnlPerson: TPanel;
    edtName: TEdit;
    lbl1: TLabel;
    lbl3: TLabel;
    edtSafe: TEdit;
    lbl4: TLabel;
    edtSalary: TEdit;
    lbl5: TLabel;
    edtPhone: TEdit;
    procedure FormCreate(Sender: TObject);
    procedure lstPersonClick(Sender: TObject);
    procedure edtNameChange(Sender: TObject);
  private
    { Private declarations }
    FMediator: TMediator;
    FObjectIndex: Integer;
  public
    { Public declarations }
  end;

var
  FormMediator: TFormMediator;

implementation

{$R *.dfm}

procedure TFormMediator.FormCreate(Sender: TObject);
var
  APerson: TPerson;
begin
  //创建mediator
  FMediator := TMediator.Create;
  //初始化列表，添加员工
  APerson := TPerson.Create;
  APerson.Name := '哈巴狗';
  APerson.SafeFee := 200;
  APerson.PhoneFee := 500;
  APerson.Salary := 5000;
  lstPerson.Items.AddObject(APerson.Name, APerson);
  APerson := TPerson.Create;
  APerson.Name := '大尾巴兔兔';
  APerson.Salary := 50000;
  APerson.SafeFee:=0;
  APerson.PhoneFee:=200;
  lstPerson.Items.AddObject(APerson.Name, APerson);
  lstPerson.ItemIndex := 0;
  //调用调停者的方法通知变更
  FObjectIndex := 0;
  FMediator.ControlChanged(lstPerson);
end;

{ TMediator }

procedure TMediator.ControlChanged(AControl: TControl);
begin
  with FormMediator do
  begin
    if AControl = edtName then
    begin
      TPerson(lstPerson.Items.Objects[FObjectIndex]).Name:=edtName.Text;
      lstPerson.Items.Strings[FObjectIndex]:=edtName.Text;
    end
    else if AControl = edtSafe then
    begin
      TPerson(lstPerson.Items.Objects[FObjectIndex]).SafeFee:=StrToFloat(edtSafe.Text);
    end
    else if AControl = edtPhone then
    begin
      TPerson(lstPerson.Items.Objects[FObjectIndex]).PhoneFee:=StrToFloat(edtPhone.Text);
    end
    else if AControl = edtSalary then
    begin
      TPerson(lstPerson.Items.Objects[FObjectIndex]).Salary:=StrToFloat(edtSalary.Text);
    end
    else if AControl=lstPerson then
    begin
      with TPerson(lstPerson.Items.Objects[FObjectIndex]) do
      begin
        edtName.Text:=Name;
        edtSafe.Text:=floattostr(SafeFee);
        edtPhone.Text:=floattostr(PhoneFee);
        edtSalary.Text:=floattostr(Salary);
      end;
    end;
  end;
end;

procedure TFormMediator.lstPersonClick(Sender: TObject);
begin
  //判断是否发生变更
  if lstPerson.ItemIndex <> FObjectIndex then
  begin
    FObjectIndex := lstPerson.ItemIndex;
    FMediator.ControlChanged(lstPerson);
  end;
end;

procedure TFormMediator.edtNameChange(Sender: TObject);
begin
  //发生变更时，更新数据
  FMediator.ControlChanged(Sender as TControl);
end;

end.