gsentityfield.pas

用Delphi实现的数据库持久化

unit gsEntityField;

(******************************************************************
  封装实体字段类型
  Copyright (c) 2005 by TinTin.
  Author : TinTin
  Date   : 2006.07
******************************************************************)

interface
uses
  SysUtils,Classes, DB, TypInfo, Contnrs, Variants;
const
  cstWrap = #13#10;
type
   //实体字段类
  TMPropFieldClass = class of TgsPropField;
  TgsPropField = class(TPersistent)
  private
    FCaption: string;
    FName: string;
    procedure SetCaption(const Value: string);
    procedure SetName(const Value: string);
  published
    property Name: string read FName write SetName;
    property Caption: string read FCaption write SetCaption;
  end;
  
  //默认有六个实体字段类
  TIntF = class(TgsPropField)
  private
    FValue: Integer;
    procedure SetValue(Value: Integer);
    function GetStrValue: string;
  published
    property Name;
    property Caption;
    property AsInt: Integer read FValue write SetValue;
    property ToStr: string read GetStrValue;
  end;

  TNumberF = class(TgsPropField)
  private
    FValue: Double;
    procedure SetValue(const Value: Double);
    function GetStrValue: string;
  published
    property Name;
    property Caption;
    property AsNum: Double read FValue write SetValue;
    property ToStr: string read GetStrValue;
  end;

  TStringF = class(TgsPropField)
  private
    FValue: Widestring;
    procedure SetValue(const Value: Widestring);
  published
    property Name;
    property Caption;
    property AsStr: Widestring read FValue write SetValue;
  end;
  TDateTimeF = class(TgsPropField)
  private
    FValue: TDateTime;
    procedure SetValue(const Value: TDateTime);
    function GetDateTimeValue: string;
    function GetDateValue: string;
    function GetTimeValue: string;
  published
    property Name;
    property Caption;
    property AsDT: TDateTime read FValue write SetValue;
    property ToDateTimeStr: string read GetDateTimeValue;
    property ToDateStr: string read GetDateValue;
    property ToTimeStr: string read GetTimeValue;
  end;
  TBooleanF = class(TgsPropField)
  private
    FValue: Boolean;
    procedure SetValue(const Value: Boolean);
    function GetStrValue: string;
  published
    property Name;
    property Caption;
    property AsBool: Boolean read FValue write SetValue;
    property ToStr: string read GetStrValue;
  end;
  TVarF = class(TgsPropField)
  private
    FValue: Variant;
    procedure SetValue(const Value: Variant);
    function GetStrValue: string;
  published
    property Name;
    property Caption;
    property AsVar: Variant read FValue write SetValue;
    property ToStr: string read GetStrValue;
  end;

  TBlobF = class(TgsPropField)
  private
    FValue: TStream;
    procedure SetValue(const Value: TStream);
  published
    property Name;
    property Caption;
    property AsBlob: TStream read FValue write SetValue;
  end;


implementation

uses Dialogs;


{ TgsPropField }

procedure TgsPropField.SetCaption(const Value: string);
begin
  FCaption := Value;
end;

procedure TgsPropField.SetName(const Value: string);
begin
  FName := Value;
end;

function TIntF.GetStrValue: string;
begin
  Result := IntToStr(FValue);
end;


procedure TIntF.SetValue(Value: Integer);
begin
  if FValue <> Value then
    FValue := Value;
end;

{ TBooleanF }

function TBooleanF.GetStrValue: string;
begin
  Result := BoolToStr(FValue);
end;

procedure TBooleanF.SetValue(const Value: Boolean);
begin
  FValue := Value;
end;

{ TDoubleF }

function TNumberF.GetStrValue: string;
begin
  Result := FloatToStr(FValue);
end;

procedure TNumberF.SetValue(const Value: Double);
begin
  FValue := Value;
end;

{ TStringF }

procedure TStringF.SetValue(const Value: Widestring);
begin
  FValue := Value;
end;

{ TDateTimeF }

function TDateTimeF.GetDateTimeValue: string;
begin
  Result := FormatDateTime('yyyy-MM-dd HH:NN:SS', FValue);
end;

function TDateTimeF.GetDateValue: string;
begin
  Result := FormatDateTime('yyyy-MM-dd', FValue);
end;

function TDateTimeF.GetTimeValue: string;
begin
  Result := FormatDateTime('HH:NN:SS', FValue);
end;

procedure TDateTimeF.SetValue(const Value: TDateTime);
begin
  FValue := Value;
end;
procedure TBlobF.SetValue(const Value: TStream);
begin
  FValue := Value;
end;

{ TVarF }

function TVarF.GetStrValue: string;
begin
  if VarIsEmpty(FValue) then
    Result :=''
  else
    Result := VarToStr(FValue);  
end;

procedure TVarF.SetValue(const Value: Variant);
begin
  FValue := Value;
end;

end.