mainunit.pas

OPC服务器及客户端编程

{------------------------------------------------------------}
{                    prOpc Toolkit                           }
{ Copyright (c) 2000, 2001 Production Robots Engineering Ltd }
{ mailto: [e-mail]                                }
{ http://www.prel.co.uk                                      }
{------------------------------------------------------------}
unit MainUnit;
{
  Client for prDemo13

  This client connects to prDemo13.exe which must be built and registered.

  The client has one group with one item. This item is defined in the server
  as an enumerated type which means that its 'Canonical Data Type' is
  VT_INTEGER. The client can, however, use the method
  TOpcGroup.ItemEnumeratedNames to retrieve a list of the names associated with
  the item. See ClientClient connect,
}


interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, prOpcClient, StdCtrls;

type
  TMainForm = class(TForm)
    ConnectButton: TButton;
    Client: TOpcSimpleClient;
    BorderStyleCB: TComboBox;
    procedure ConnectButtonClick(Sender: TObject);
    procedure ClientConnect(Sender: TObject);
    procedure ClientDisconnect(Sender: TObject);
    procedure BorderStyleCBSelect(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation

{$R *.dfm}

procedure TMainForm.ConnectButtonClick(Sender: TObject);
begin
  if Client.Active then
  begin
    Client.Active:= false;
    ConnectButton.Caption:= 'Connect'
  end else
  begin
    Client.Active:= true;
    ConnectButton.Caption:= 'Disconnect'
  end
end;

procedure TMainForm.ClientConnect(Sender: TObject);
begin
  {retrieve enumerated names from client}
  Client.Groups[0].ItemEnumeratedNames(0, BorderStyleCB.Items);
  BorderStyleCB.ItemIndex:= Client.Groups[0].ItemValue[0];
  BorderStyleCB.Enabled:= true
end;

procedure TMainForm.ClientDisconnect(Sender: TObject);
begin
  BorderStyleCB.Enabled:= false;
  BorderStyleCB.Items.Clear;
  BorderStyleCB.ItemIndex:= -1
end;

procedure TMainForm.BorderStyleCBSelect(Sender: TObject);
begin
  if BorderStyleCB.Enabled then
    Client.Groups[0].ItemValue[0]:= BorderStyleCB.ItemIndex
end;

end.