delphi数据库

Question

下面的代码中这一句为什么adoconnection1.ConnectionString:=format(conststr,[provider.text,dataprovider.text,edtdatasource.text]);
老出现错误，是不是我定义错了！！还望大家多帮帮忙，谢谢！（还望讲讲format的具体使用方法，什么时候一般要用？）unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, DBGrids, StdCtrls, ExtCtrls, ADODB, DB, DBTables,
  ComCtrls;type
  TForm1 = class(TForm)
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    Panel1: TPanel;
    DataSource1: TDataSource;
    Table1: TTable;
    Database1: TDatabase;
    ADOConnection1: TADOConnection;
    ADOTable1: TADOTable;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    ADOConnection2: TADOTable;
    DataSource2: TDataSource;
    OpenDialog2: TOpenDialog;
    BtnOpen: TButton;
    RadioGroup1: TRadioGroup;
    DBGrid1: TDBGrid;
    BtnBrowser: TButton;
    BtOpenFile: TButton;
    Tabel1: TButton;
    provider: TEdit;
    Edit1: TEdit;
    EdtDataSource: TEdit;
    ComboBox1: TComboBox;
    BtnOpen2: TButton;
    BtnBrowser2: TButton;
    ComboBox2: TComboBox;
    DBGrid2: TDBGrid;
    edtDriver: TEdit;
    EdtDataBase: TEdit;
    procedure BtnOpenClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.BtnOpenClick(Sender: TObject);
const
   conststr='provider=%s ;data provider=%s;data source=%s';
begin
    if not adoconnection1.Connected then
   adoconnection1.ConnectionString:=format(conststr,[provider.text,dataprovider.text,edtdatasource.text]);
    try
    adoconnection1.Open();
    except
       exception.create(conopenadoerror);
end;end.

Answer 1

format没有错，你看看错误提示是什么，弄清楚是谁的错误

Answer 2

在你的format那一句里面打个断点测试跟踪一下执行前和执行后你的ConnectionString是什么值，你就知道了！

Answer 3

还望朋友们能帮下忙！！我的下面的程序又出问题了！找了好久都是没找到！！出错住处显示的是adoconnection1.GetTableNames(cbtablename.items,false);这一句。[Error] Unit1.pas(69): Record, object or class type required
[Fatal Error] Project1.dpr(5): Could not compile used unit 'Unit1.pas'unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, DBGrids, StdCtrls, ExtCtrls, ADODB, DB, DBTables,
  ComCtrls;type
  TForm1 = class(TForm)
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    Panel1: TPanel;
    DataSource1: TDataSource;
    Table1: TTable;
    Database1: TDatabase;
    ADOConnection1: TADOConnection;
    ADOTable1: TADOTable;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    ADOConnection2: TADOTable;
    DataSource2: TDataSource;
    OpenDialog2: TOpenDialog;
    BtnOpen: TButton;
    RadioGroup1: TRadioGroup;
    DBGrid1: TDBGrid;
    BtnBrowser: TButton;
    BtOpenFile: TButton;
    Tabel1: TButton;
    provider: TEdit;
    Edit1: TEdit;
    EdtDataSource: TEdit;
    ComboBox1: TComboBox;
    BtnOpen2: TButton;
    BtnBrowser2: TButton;
    ComboBox2: TComboBox;
    DBGrid2: TDBGrid;
    edtDriver: TEdit;
    EdtDataBase: TEdit;
    procedure BtnOpenClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.BtnOpenClick(Sender: TObject);
const
  conststr='provider=%s ;data provider=%s;data source=%s';
  var
     cbtablename:string;
begin
  if not adoconnection1.Connected then
  adoconnection1.ConnectionString:=format(conststr,[provider.text,provider.text,edtdatasource.text]);
  try
  adoconnection1.Open();
  except
  exception.create('conopenadoerror');
end;
  adoconnection1.GetTableNames(cbtablename.items,false);
  cbtablename.itemindex:=0;
  adotable1.close;
  adotable.connection:=adoconnection1;
  adotable1.tablename:=cbtablename.text;
  adotable.open;
end;end.