15.2.3 TSession部件應(yīng)用舉例
例15.1：我們創(chuàng)建一個(gè)應(yīng)用程序，通過(guò)調(diào)用TSession有關(guān)的方法獲取當(dāng)前應(yīng)用程序可以進(jìn)行連接的數(shù)據(jù)庫(kù)的名字以及獲取其中任意一個(gè)數(shù)據(jù)庫(kù)中的全部數(shù)據(jù)庫(kù)表的名字。
通過(guò)TSession部件獲取數(shù)據(jù)庫(kù)的有關(guān)信息
窗體中主要使用了兩個(gè)列表框，其中列表框DatabaselistBox用于顯示數(shù)據(jù)庫(kù)的名字，列表框TablelistBox用于顯示數(shù)據(jù)庫(kù)中的表名。程序運(yùn)行完后數(shù)據(jù)庫(kù)的名字顯示在DatabaselistBox列表框中，當(dāng)用戶單擊DatabaselistBox列表框中的數(shù)據(jù)庫(kù)名時(shí)，該數(shù)據(jù)庫(kù)全部的數(shù)據(jù)庫(kù)表的名字將會(huì)顯示在TablelistBox列表框中。有關(guān)的程序代碼如下：
程序清單15.1
unit unit31;
interface
uses
SysUtils, Windows, Messages, Classes, Graphics, Controls,
Forms, Dialogs, StdCtrls, DB, DBTables, Buttons, ComCtrls, Tabnotbk;
type
TQueryForm = class（TForm）
BitBtn1: TBitBtn;
DataSource1: TDataSource;
Table1: TTable;
GroupBox1: TGroupBox;
CheckBox1: TCheckBox;
CheckBox2: TCheckBox;
PageControl1: TPageControl;
TabSheet1: TTabSheet;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
ListBox1: TListBox;
ListBox2: TListBox;
ListBox3: TListBox;
TabSheet2: TTabSheet;
Memo1: TMemo;
procedure FormCreate（Sender: TObject）;
procedure ListBox1Click（Sender: TObject）;
procedure ListBox2Click（Sender: TObject）;
end;
var
QueryForm: TQueryForm;
implementation
{$R *.DFM}
uses RSLTFORM;
procedure TQueryForm.FormCreate（Sender: TObject）;
begin
Screen.Cursor := crHourglass;
{ Populate the alias list }
with ListBox1 do
begin
Items.Clear;
Session.GetAliasNames（Items）;
end;
{ Make sure there are aliases defined }
Screen.Cursor := crDefault;
if ListBox1.Items.Count < 1 then
MessageDlg（ 'There are no database aliases currently defined. You ' +
'need at least one alias to use this demonstration.',
mtError, [mbOK], 0 ）;
end;
procedure TQueryForm.ListBox1Click（Sender: TObject）;
var
strValue: string; { Holds the alias selected by the user }
bIsLocal: Boolean; { Indicates whether or not an alias is local }
slParams: TStringList; { Holds the parameters of the selected alias }
iCounter: Integer; { An integer counter variable for loops}
begin
{ Determine the alias name selected by the user }
with ListBox1 do
strValue := Items.Strings[ItemIndex];
{ Get the names of the tables in the alias and put them in the
appropriate list box, making sure the user's choices are reflected
in the list. }
ListBox2.Items.Clear;
Session.GetTableNames（strValue, { alias to enumerate }
'', { pattern to match }
例15.1：我們創(chuàng)建一個(gè)應(yīng)用程序，通過(guò)調(diào)用TSession有關(guān)的方法獲取當(dāng)前應(yīng)用程序可以進(jìn)行連接的數(shù)據(jù)庫(kù)的名字以及獲取其中任意一個(gè)數(shù)據(jù)庫(kù)中的全部數(shù)據(jù)庫(kù)表的名字。
通過(guò)TSession部件獲取數(shù)據(jù)庫(kù)的有關(guān)信息
窗體中主要使用了兩個(gè)列表框，其中列表框DatabaselistBox用于顯示數(shù)據(jù)庫(kù)的名字，列表框TablelistBox用于顯示數(shù)據(jù)庫(kù)中的表名。程序運(yùn)行完后數(shù)據(jù)庫(kù)的名字顯示在DatabaselistBox列表框中，當(dāng)用戶單擊DatabaselistBox列表框中的數(shù)據(jù)庫(kù)名時(shí)，該數(shù)據(jù)庫(kù)全部的數(shù)據(jù)庫(kù)表的名字將會(huì)顯示在TablelistBox列表框中。有關(guān)的程序代碼如下：
程序清單15.1
unit unit31;
interface
uses
SysUtils, Windows, Messages, Classes, Graphics, Controls,
Forms, Dialogs, StdCtrls, DB, DBTables, Buttons, ComCtrls, Tabnotbk;
type
TQueryForm = class（TForm）
BitBtn1: TBitBtn;
DataSource1: TDataSource;
Table1: TTable;
GroupBox1: TGroupBox;
CheckBox1: TCheckBox;
CheckBox2: TCheckBox;
PageControl1: TPageControl;
TabSheet1: TTabSheet;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
ListBox1: TListBox;
ListBox2: TListBox;
ListBox3: TListBox;
TabSheet2: TTabSheet;
Memo1: TMemo;
procedure FormCreate（Sender: TObject）;
procedure ListBox1Click（Sender: TObject）;
procedure ListBox2Click（Sender: TObject）;
end;
var
QueryForm: TQueryForm;
implementation
{$R *.DFM}
uses RSLTFORM;
procedure TQueryForm.FormCreate（Sender: TObject）;
begin
Screen.Cursor := crHourglass;
{ Populate the alias list }
with ListBox1 do
begin
Items.Clear;
Session.GetAliasNames（Items）;
end;
{ Make sure there are aliases defined }
Screen.Cursor := crDefault;
if ListBox1.Items.Count < 1 then
MessageDlg（ 'There are no database aliases currently defined. You ' +
'need at least one alias to use this demonstration.',
mtError, [mbOK], 0 ）;
end;
procedure TQueryForm.ListBox1Click（Sender: TObject）;
var
strValue: string; { Holds the alias selected by the user }
bIsLocal: Boolean; { Indicates whether or not an alias is local }
slParams: TStringList; { Holds the parameters of the selected alias }
iCounter: Integer; { An integer counter variable for loops}
begin
{ Determine the alias name selected by the user }
with ListBox1 do
strValue := Items.Strings[ItemIndex];
{ Get the names of the tables in the alias and put them in the
appropriate list box, making sure the user's choices are reflected
in the list. }
ListBox2.Items.Clear;
Session.GetTableNames（strValue, { alias to enumerate }
'', { pattern to match }