tvalueobjectlistunit.pas

随便说说最近项目中的三层架构吧。讲点实际的东西。我最讨厌空讲道理。网上讲道理的太多了

//------------------------------------------------------------------------------
//                        VOList值列表组装器基类
//1.只和VO打交道，与VO来源无关(数据库，EXCEL，XML等，不关心底层)。
//2.提供VO的基本操纵方法(新增，删除，获取, 更新, 导航功能)。
//3.提供了TVOList<->OleVariant的互换功能。
//4.VOList的派生类应能获取多种数据源(File, XML，内存流等）。
//------------------------------------------------------------------------------


unit TValueObjectListUnit;

interface

uses
   Windows,Classes, SysUtils,  Forms, Dialogs, DB, ADODB,
   Contnrs, Variants, DBClient, ValueObjectUnit;

type

  PTValueObjectList =^ TValueObjectList;
  TValueObjectList = Class(TObjectList)
    private
      sVOClass: String;  //实际要生成的VO对象.
      ValueObject: TValueObject;
      PIndex: Integer;

      function getVOClass: String;
      procedure SetVOClass(sTmpClass: String);
      procedure setValueObject(pTmpVO :TValueObject);
      function getValueObject: TValueObject;
   protected
      function GetOLEData: OleVariant; virtual;
      procedure SetOLEData(const Value: OleVariant); virtual;
      function GetVO: TValueObject;  overload;
      function GetVO(index: Integer): TValueObject;  overload;
   published
      property pVOClass: String read getVOClass write setVOClass;
      //--TValueObject--
      function FindVO(AObject: TValueObject ):Integer; virtual;
      function SetVo(AObject: TValueObject ):Integer; virtual;
      function NewVO: TValueObject; virtual;
      function AddVO(AObject: TValueObject ):Integer; virtual;
      function DelVO(index: integer; AObject: TValueObject ):Integer; virtual;
      function FirstVO: TValueObject; virtual;
      function PriorVO: TValueObject; virtual;
      function NextVO: TValueObject; virtual;
      function EndVO: TValueObject; virtual;
      function CountVO:Integer; virtual;
    public
      constructor Create;
      destructor Destroy; override;
      procedure AfterConstruction; override;
      property POLEData: OleVariant read GetOLEData write SetOLEData;
      property PValueObject: TValueObject read getValueObject write setValueObject;
   end;


implementation

//----------------------------- TValueObjectList---------------------------------
constructor TValueObjectList.Create;
begin
  inherited Create;
  PIndex := 0;
end;

function TValueObjectList.getVOClass: String;
begin
  Result := sVOClass;
end;

procedure TValueObjectList.SetVOClass(sTmpClass: String);
begin
  sVOClass := sTmpClass;
end;

procedure TValueObjectList.setValueObject(pTmpVO :TValueObject);
begin
  ValueObject := pTmpVO;
end;

function TValueObjectList.getValueObject: TValueObject;
begin
  Result := ValueObject;
end;

procedure TValueObjectList.AfterConstruction;
begin
  inherited;
end;

destructor TValueObjectList.Destroy;
begin
  inherited;
end;

procedure TValueObjectList.SetOLEData(const Value: OleVariant);
var
  i_i: integer;
  tmpPer: TPersistent;
begin
  if not VarIsArray(Value) then
    Exit;
  Clear;
  for i_i:=0 to VarArrayHighBound(Value,1) do
  begin
    ValueObject := NewVO;
    ValueObject.POLEData := Value[i_i];
    Add(ValueObject);
  end;

end;

function TValueObjectList.GetOLEData: OleVariant;
var
  i_i, i_iCount: Integer;
begin
  if Count=0 then
  begin
    TVarData(Result).VType := varEmpty;
    Exit;
  end;
  i_iCount := Count;
  Result := VarArrayCreate([0, i_iCount-1], varVariant);
  for i_i:=0 to i_iCount-1 do
  begin
    ValueObject := TValueObject(Items[i_i]);
    Result[i_i] := ValueObject.POLEData;
  end;
end;

//--TValueObject--
function TValueObjectList.NewVO: TValueObject;
var
  tmpPer: TPersistent;
begin
  if FindClass(pVOClass) <> nil then
  begin
    tmpPer := TPersistentClass(FindClass(pVOClass)).Create;
    Result := TValueObject(tmpPer);
  end
  else
    Result := TValueObject.Create;
end;

function TValueObjectList.AddVO(AObject: TValueObject ):Integer;
begin
  Result := Add(AObject);
end;

function TValueObjectList.FindVO(AObject: TValueObject ):Integer;
var
  i_i: Integer;
  tmpVO: TValueObject;
  b_flag: Boolean;
begin
  b_flag := false;
  for i_i :=0 to CountVO-1 do
  begin
    tmpVO := GetVO(i_i);
    if tmpVO.pPrimarykey= AObject.pPrimarykey then
    begin
      b_flag := true;
      break;
    end;
  end;

  if b_flag then
    Result := i_i
  else
    Result := -1;

end;

function TValueObjectList.GetVO: TValueObject;
begin
  ValueObject := TValueObject(Items[PIndex]);
  Result := TValueObject(Items[PIndex]);
end;

function TValueObjectList.SetVo(AObject: TValueObject ):Integer;
var
  i_rtn: Integer;
  tmpVO: TValueObject;
begin
  i_rtn := FindVO(AObject);
  if i_rtn<>-1 then
  begin
    tmpVO := GetVO(i_rtn);
    tmpVO := AObject;
    Result := 1;
  end
  else
    Result := -1;

end;

function TValueObjectList.DelVO(index: integer; AObject: TValueObject ):Integer;
var
  tmpVO: TValueObject;
  i_rtn: Integer;
begin
  i_rtn := FindVO(AObject);

  if i_rtn<>-1 then
  begin
    tmpVO := getVO(i_rtn);
    Result := Remove(tmpVO);
  end
  else
    Result := -1;
end;

function TValueObjectList.GetVO(index: Integer): TValueObject;
begin
  if (index>=0) and (index<CountVO) then
    Result := TValueObject(Items[index]);
end;

function TValueObjectList.FirstVO: TValueObject;
begin
  Result := GetVO(0);
  PIndex := 0;
end;

function TValueObjectList.PriorVO: TValueObject;
begin
  Dec(PIndex);
  Result := TValueObject(Items[PIndex]);
end;

function TValueObjectList.NextVO: TValueObject;
begin
  Inc(PIndex);
  Result := TValueObject(Items[PIndex]);
end;

function TValueObjectList.EndVO: TValueObject;
begin
  Result := GetVO(CountVO-1);
  PIndex := CountVO-1;
end;

function TValueObjectList.CountVO: Integer;
begin
  Result := Count;
end;

end.