Componentes.Terceros.RemObjects/internal/5.0.24.615/1/Data Abstract for Delphi/Samples/Connection By User/ConnectionByUserMain.pas

unit ConnectionByUserMain;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, uDAClasses, uDADriverManager, uDAEngine, uDAADODriver,
  uROSessions, uROClient;

type
  TConnectionByUserMainForm = class(TForm)
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Label2: TLabel;
    eUserID: TEdit;
    ePassword: TEdit;
    Acquire1Button: TButton;
    Acquire2Button: TButton;
    Acquire3Button: TButton;
    DAADODriver: TDAADODriver;
    DADriverManager: TDADriverManager;
    DAConnectionManager: TDAConnectionManager;
    Acquire4Button: TButton;
    ROSessionManager: TROInMemorySessionManager;
    AcquireHoldButton: TButton;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Label6: TLabel;
    Memo: TMemo;
    procedure Acquire1ButtonClick(Sender: TObject);
    procedure Acquire2ButtonClick(Sender: TObject);
    procedure Acquire3ButtonClick(Sender: TObject);
    procedure Acquire4ButtonClick(Sender: TObject);
    procedure AcquireHoldButtonClick(Sender: TObject);
  private
    { Private declarations }
    procedure Log(Str: string);
  public
    { Public declarations }
  end;

var
  ConnectionByUserMainForm: TConnectionByUserMainForm;

implementation

uses uDAInterfaces;

{$R *.dfm}

procedure TConnectionByUserMainForm.Acquire1ButtonClick(Sender: TObject);
var
  conn: IDAConnection;
begin
  try
    conn := DAConnectionManager.NewConnection('ADOComplete');
  finally
    if (Conn <> nil) and conn.Connected then begin
      Log(TButton(Sender).Caption + ': Connection successful');
      log('Connection via "' + conn.ConnectionString + '"');
    end
    else begin
      Log(TButton(Sender).Caption + ': Connection failed');
    end;
  end;
end;

procedure TConnectionByUserMainForm.Acquire2ButtonClick(Sender: TObject);
var
  conn: IDAConnection;
begin
  try
    conn := DAConnectionManager.NewConnection('ADOPartial', FALSE);
    conn.UserID := eUserID.Text;
    conn.Password := ePassword.Text;
    conn.Open;
  finally
    if (Conn <> nil) and conn.Connected then begin
      Log(TButton(Sender).Caption + ': Connection successful');
      log('Connection via "' + conn.ConnectionString + '"');
    end
    else begin
      Log(TButton(Sender).Caption + ': Connection failed');
    end;
  end;
end;

procedure TConnectionByUserMainForm.Acquire3ButtonClick(Sender: TObject);
var
  conn: IDAConnection;
begin
  try
    conn := DAConnectionManager.NewConnection('ADOPartial', TRUE, eUserID.Text, ePassword.Text);
  finally
    if (Conn <> nil) and conn.Connected then begin
      Log(TButton(Sender).Caption + ': Connection successful');
      log('Connection via "' + conn.ConnectionString + '"');
    end
    else begin
      Log(TButton(Sender).Caption + ': Connection failed');
    end;
  end;
end;

procedure TConnectionByUserMainForm.Acquire4ButtonClick(Sender: TObject);
var
  drv: IDADriver;
  conn: IDAConnection;
begin
  try
    drv := DriverManager.DriverByDriverID('ADO'); // Raises exception if not found
    conn := drv.NewConnection;
    // If not empty strings, these will override any specific UserID, Password specified below
    conn.ConnectionString := Format('Server=localhost;Database=Northwind;AuxDriver=SQLOLEDB.1;UserID=%s;Password=%s;', [eUserID.Text, ePassword.Text]);
    conn.Open;
  finally
    if (Conn <> nil) and conn.Connected then begin
      Log(TButton(Sender).Caption + ': Connection successful');
      log('Connection via "' + conn.ConnectionString + '"');
    end
    else begin
      Log(TButton(Sender).Caption + ': Connection failed');
    end;
  end;
end;

procedure TConnectionByUserMainForm.AcquireHoldButtonClick(Sender: TObject);
const
  MySessionID: TGUID = '{2B0ABD74-465A-45A6-AAD7-837709A66DB9}';
var
  session: TROSession;
  conn: IDAConnection;
begin

  conn := DAConnectionManager.NewConnection('ADOComplete');

  with ROSessionManager do try
    session := CreateSession(MySessionID);

    // #1: How to store IDAConnections in RO sessions ----------------------------------------
    conn._AddRef; // We increment its ref count because we want it locked by the session
    session.Values['MyADOConnection'] := integer(conn);
    // End of #1 -----------------------------------------------------------------------------

    conn := nil; // We set it to NIL to simulate what would happen in a real RO Datamodule when the vars get out of scope
    ReleaseSession(session, TRUE);
{$WARNINGS OFF}
    session := nil; // Just to simulate real re-initialization
{$WARNINGS ON}
    session := FindSession(MySessionID);

    // #2: How to get IDAConnections from RO Sessions ----------------------------------------
    try
      conn := IDAConnection(pointer(integer(session.Values['MyADOConnection'])));
    finally
      if (Conn <> nil) and conn.Connected then begin
        Log(TButton(Sender).Caption + ': Connection successful');
        log('Connection via "' + conn.ConnectionString + '"');
      end
      else begin
        Log(TButton(Sender).Caption + ': Connection failed');
      end;
    end;

    // End of #2 -----------------------------------------------------------------------------

    // #3: How to finally release the connection from the session. This should be done when you ------
    // want to get rid of the connection for good...
    conn.Close; // Optional. Implicit when it gets freed
    conn._Release; // Removes the lock we imposed on the connection at the very beginning
    // End of #3 -------------------------------------------------------------------------------------

    conn := nil; // This is only useful in this example because the ref count is still held up to one by the local "conn" variable.

  finally
    DeleteSession(MySessionID, FALSE); // This is what the RO session manager does for you, so ignore this too
  end;
end;

procedure TConnectionByUserMainForm.Log(Str: string);
begin
  Memo.Lines.Add(Str);
end;

end.