datarange.pas

《delphi数据库设计与实例开发》随书光盘

unit DataRange;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, Grids, DBGrids, DBTables;

type
  TForm1 = class(TForm)
    Table1: TTable;
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    GroupBox1: TGroupBox;
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Label1: TLabel;
    Label2: TLabel;
    GroupBox2: TGroupBox;
    Label4: TLabel;
    Edit3: TEdit;
    Edit4: TEdit;
    Button6: TButton;
    Label3: TLabel;
    Label5: TLabel;
    Button7: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Button6Click(Sender: TObject);
    procedure Button7Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
with Table1 do
 begin
  SetRangeStart; //设置开始值
  FieldByName('CustNo').AsInteger:=StrtoInt(edit1.Text);
  SetRangeEnd; //设置结束值
  FieldByName('CustNo').Asinteger:=StrtoInt(edit2.Text);
  ApplyRange; //通知数据集应用搜索范围
  Refresh; //刷新数据集，应用搜索范围
end;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 try
  Table1.DatabaseName:='DBDEMOS';
  Table1.TableName:='customer.db';
  Table1.IndexFieldNames:='CustNo';
  Table1.Active:=true;
 except
  On E:EdatabaseError do
  ShowMessage(E.Message);
 end;
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
with Table1 do
 begin
 if edit3.Text<>'' then
  begin
   EditRangeStart; //修改开始值
   FieldByName('CustNo').Asinteger:=StrtoInt(edit3.Text);
  end;
 if edit4.Text<>'' then
  begin
   EditRangeEnd;  //修改结束值
   FieldByName('CustNo').Asinteger:=StrtoInt(edit4.Text);
  end;
   ApplyRange; //通知数据集应用搜索范围
   Refresh; //刷新数据集，应用搜索范围
end;

end;

procedure TForm1.Button7Click(Sender: TObject);
begin
 Table1.CancelRange;
 Table1.Refresh;
 edit1.Text:='';
 edit2.Text:='';
 edit3.Text:='';
 edit4.Text:='';
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
 Table1.FindFirst;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
 Table1.FindPrior;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
 Table1.FindNext;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
 Table1.FindLast;
end;

end.