urdmlargedatasetdemo.pas

来自「就是这本书的随书代码。包括《实战Delphi 5.x-分布式多层应用系统篇》」· PAS 代码 · 共 101 行

unit urdmLargeDataSetDemo;

interface

uses
  Windows, Messages, SysUtils, Classes, ComServ, ComObj, VCLCom, DataBkr,
  DBClient, PLargeDataSetDemoServer_TLB, StdVcl, Db, DBTables, Provider;

type
  TldsDemoServer = class(TRemoteDataModule, IldsDemoServer)
    Database1: TDatabase;
    Query1: TQuery;
    DataSetProvider1: TDataSetProvider;
    dspGeneral: TDataSetProvider;
    quryGeneral: TQuery;
    tblDataRequest: TTable;
    dspDataRequest: TDataSetProvider;
    procedure DataSetProvider1BeforeGetRecords(Sender: TObject;
      var OwnerData: OleVariant);
    procedure RemoteDataModuleCreate(Sender: TObject);
    procedure RemoteDataModuleDestroy(Sender: TObject);
    function DataSetProvider1DataRequest(Sender: TObject;
      Input: OleVariant): OleVariant;
    function dspDataRequestDataRequest(Sender: TObject;
      Input: OleVariant): OleVariant;
  private
    { Private declarations }
  protected
    class procedure UpdateRegistry(Register: Boolean; const ClassID, ProgID: string); override;
  public
    { Public declarations }
  end;

implementation

{$R *.DFM}

class procedure TldsDemoServer.UpdateRegistry(Register: Boolean; const ClassID, ProgID: string);
begin
  if Register then
  begin
    inherited UpdateRegistry(Register, ClassID, ProgID);
    EnableSocketTransport(ClassID);
    EnableWebTransport(ClassID);
  end else
  begin
    DisableSocketTransport(ClassID);
    DisableWebTransport(ClassID);
    inherited UpdateRegistry(Register, ClassID, ProgID);
  end;
end;

procedure TldsDemoServer.DataSetProvider1BeforeGetRecords(Sender: TObject;
  var OwnerData: OleVariant);
begin
  with Sender as TDataSetProvider do
  begin
    DataSet.Open;
    DataSet.Locate('NUM', OwnerData, []);
    DataSet.Next;
  end;
end;

procedure TldsDemoServer.RemoteDataModuleCreate(Sender: TObject);
begin
  Database1.Connected := True;
  Query1.Active := True;
end;

procedure TldsDemoServer.RemoteDataModuleDestroy(Sender: TObject);
begin
  Database1.CloseDataSets;
  Database1.Connected := False;
end;

function TldsDemoServer.DataSetProvider1DataRequest(Sender: TObject;
  Input: OleVariant): OleVariant;
begin
  Query1.SQL.Text := Input;
  Query1.Open;
  Result := DataSetProvider1.Data;
end;

function TldsDemoServer.dspDataRequestDataRequest(Sender: TObject;
  Input: OleVariant): OleVariant;
begin
  with tblDataRequest do
  begin
    SetRangeStart;
    FieldByName('NUM').AsString := Input;
    SetRangeEnd;
    FieldByName('NUM').AsString := '010361';
    ApplyRange;
  end;
end;

initialization
  TComponentFactory.Create(ComServer, TldsDemoServer,
    Class_ldsDemoServer, ciMultiInstance, tmApartment);
end.