child_sort.pas

一个桌面数据库应用的源码,适合初学数据库编程的新手.

unit Child_Sort;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons, Db, DBTables, Grids, DBGrids, ExtCtrls, DBCtrls;

type
  Tfrm_Sort = class(TForm)
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    OpenDialog1: TOpenDialog;
    Panel1: TPanel;
    Edit1: TEdit;
    ComboBox1: TComboBox;
    Label1: TLabel;
    Query1: TQuery;
    Table1: TTable;
    DBNavigator1: TDBNavigator;
    SpeedButton1: TSpeedButton;
    SpeedButton2: TSpeedButton;
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormShow(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure DataSource1DataChange(Sender: TObject; Field: TField);
    procedure SpeedButton2Click(Sender: TObject);
    procedure SpeedButton1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frm_Sort: Tfrm_Sort;

implementation

uses Main;

{$R *.DFM}

procedure Tfrm_Sort.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  with Mainform do
  begin
    if MDIChildCount=1 then
      StatusBar.Panels[1].Text:='';
  end;
  Query1.Close;
  Action:=caFree;
end;

procedure Tfrm_Sort.FormShow(Sender: TObject);
begin
  OpenDialog1.InitialDir:=MainForm.GetExePath+'mdb';
end;

procedure Tfrm_Sort.FormCreate(Sender: TObject);
begin
  Height:=Constraints.MinHeight;
  Width:=Constraints.MinWidth;
  Panel1.Align:=alTop;
  DBGrid1.Align:=alClient;
end;

procedure Tfrm_Sort.FormActivate(Sender: TObject);
begin
  if (Table1.Active)or(Query1.Active) then
    MainForm.StatusBar.Panels[1].Text:='排序浏览纪录导航信息：第'+inttostr(DataSource1.DataSet.RecNo)+'笔纪录-总共'+inttostr(DataSource1.DataSet.RecordCount)+'笔纪录';
end;

procedure Tfrm_Sort.DataSource1DataChange(Sender: TObject; Field: TField);
begin
  FormActivate(Sender);
end;

procedure Tfrm_Sort.SpeedButton2Click(Sender: TObject);
var
  I:integer;
begin
  if OpenDialog1.Execute then
  begin
    try
      Query1.Close;
      Table1.Close;
      Table1.DatabaseName:=ExtractFilePath(OpenDialog1.FileName);
      Table1.TableName:=OpenDialog1.FileName;
      Edit1.Text:=OpenDialog1.FileName;
      Table1.Open;
      ComboBox1.Clear;
      for I := 0 to Table1.FieldDefs.Count-1  do
        ComboBox1.Items.Add(Table1.FieldDefs.Items[i].Name);
      ComboBox1.ItemIndex:=0;
      Table1.Close;
    except
      ShowMessage('无法打开的数据库文件');
    end;
  end;
end;

procedure Tfrm_Sort.SpeedButton1Click(Sender: TObject);
var
  DBName,FieldName:string;
begin
  try
    DBName:=Edit1.Text;
    FieldName:=ComboBox1.Text;
    Query1.SQL.Clear;
    Query1.SQL.Add('SELECT * FROM "'+DBName+'" Order by '+FieldName);
    Query1.Prepare;
    Query1.ExecSQL;
    Query1.Open;
  except
    ShowMessage('错误，空数据库或者无效数据库');
  end;
end;

end.