flargedatasetclient2main.pas

delphi多层应用系统 delphi多层应用系统

unit fLargeDataSetClient2Main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  Db, DBClient, MConnect, SConnect, Grids, DBGrids, StdCtrls, ExtCtrls,
  DBCtrls;

type
  TForm3 = class(TForm)
    DBNavigator1: TDBNavigator;
    Panel1: TPanel;
    edtSearchField: TEdit;
    edtRecNo: TEdit;
    edtTime: TEdit;
    btnLocate: TButton;
    btnMore: TButton;
    DBGrid1: TDBGrid;
    ClientDataSet1: TClientDataSet;
    SocketConnection1: TSocketConnection;
    DataSource1: TDataSource;
    cdsGeneral: TClientDataSet;
    cdsTemp: TClientDataSet;
    DataSource2: TDataSource;
    DBNavigator2: TDBNavigator;
    DBGrid2: TDBGrid;
    ClientDataSet2: TClientDataSet;
    btn2More: TButton;
    procedure btnLocateClick(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure FormDeactivate(Sender: TObject);
    procedure ClientDataSet1BeforeGetRecords(Sender: TObject;
      var OwnerData: OleVariant);
    procedure btnMoreClick(Sender: TObject);
    procedure ClientDataSet2BeforeGetRecords(Sender: TObject;
      var OwnerData: OleVariant);
    procedure btn2MoreClick(Sender: TObject);
  private
    { Private declarations }
    vOwnerData : OleVariant;
    bTrueEOF : Boolean;
    bTrueEOF2 : Boolean;
    v2OwnerData : OleVariant;

    function GetKeyFieldValue(Sender : TObject) : OleVariant;
  public
    { Public declarations }
  end;

var
  Form3: TForm3;

implementation

{$R *.DFM}


procedure TForm3.btnLocateClick(Sender: TObject);
var
  lStart, lEnd : Integer;
  lCurr, lOffset : Integer;

  procedure CheckData;
  var
    iCount : Integer;
  begin
    cdsTemp.Data := ClientDataSet1.Data;
    while not (cdsGeneral.Eof) do
    begin
      if (cdsTemp.Locate('NUM', cdsGeneral.FieldByName('NUM').Value, []) ) then
        cdsGeneral.Delete
      else
        cdsGeneral.Next;
    end;
    cdsGeneral.MergeChangeLog;
  end;
begin
  lStart := GetTickCount;

  if not (ClientDataSet1.Locate('NAME', edtSearchField.Text, [loPartialKey, loCaseInsensitive]) ) then
  begin
    cdsGeneral.Close;
    if (edtSearchField.Text = '*') then
    begin
      cdsGeneral.Active := False;
      cdsGeneral.Active := True;
    end
    else
    begin
      cdsGeneral.CommandText := 'select * from cust where NAME like ' + '''' + edtSearchField.Text + '%''';
      cdsGeneral.Open;
      if (cdsGeneral.RecordCount > 0) then
      begin
        lCurr := ClientDataSet1.RecNo;
        lOffset := ClientDataSet1.RecordCount - lCurr + 1;
        CheckData;
        ClientDataSet1.AppendData(cdsGeneral.Data, False);
        ClientDataSet1.MoveBy(lOffset);
      end;
    end;
  end;

  edtRecNo.Text := IntToStr(ClientDataSet1.RecordCount);
  lEnd := GetTickCount;
  edtRecNo.Text := IntToStr(ClientDataSet1.RecordCount);
  edtTime.Text := FloatToStr((lEnd - lStart) / 1000.0) + '