Version 8.3.4	SEARCH   CONTENTS   |   PDF BOOKS   |   HOME   UP   PREV   NEXT

This is a "hot topic": embedding ActiveX controls in pages. Before telling you what the control does, let us explain why we do it:

Of course, the client integration of ActiveX controls has - from browser or SWT perspective - only disadvantages:

• ActiveX controls are not secure: you decide to run one control or not. But do not have a "sandbox" as you have with JavaScript or with applets. Using an ActiveX control means that this contol - once running - has native access to your computer, just as any other native program.

• ActiveX controls are bound to the Microsoft Windows platform.

• ActiveX controls need to be explicitly installed on the client side - maybe automated in some way, but still an explicit installation is necessary.

But - and this is why we support them - in some cases, they are a nice way to integrate other software which runs out of the scope of the browser.

Example: you may want to integrate your user interface with a barcode reader which is connected to your client via a serial interface. In this case, there is no way to access this barcode reader via JavaScript. You need to use an ActiveX control (or a signed applet) to connect to the serial device.

There is a simple interface between HTML/JavaScript and ActiveX, and vice versa. ActiveX controls can be embedded into an HTML page and it is possible to directly access properties of the ActiveX control from JavaScript. This interface was used for building the ACTIVEX control that you can use as an Application Designer control. Calling methods in the ACTIVEX or send/receive events is not supported.

The following topics are covered below:

• Example

• Properties

Example

Have a look at the following screen:

Within the normal Application Designer controls, you see a calendar control: this calendar control is an ActiveX control. When choosing the Get Date button, the date of the calendar is displayed within the field below.

Let us have a look at the XML layout definition:

<rowarea name="ActiveX Control" height="100%">
    <itr takefullwidth="true" height="100%">
        <activex classid="8E27C92B-1264-101C-8A2F-040224009C02"
                 progid="MSCAL.Calendar"
                 getxparams="year;adapterYear;month;adapterMonth;day;adapterDay"
                 width="100%" height="100%">
        </activex>
    </itr>
    <vdist height="12">
    </vdist>
    <itr>
        <button name="Get Date" method="onGetDate">
        </button>
        <hdist width="12">
        </hdist>
        <field valueprop="date" width="200" datatype="date">
        </field>
    </itr>
</rowarea>

The ActiveX control links via a classid and a progid to the ActiveX component that is used. It has a property getxparams: in this property, pairs of properties are listed, each pair being the name of the ActiveX component's property and the one of the adapter property. When using getxparams, the ActiveX properties are transferred into the adapter properties with every roundtrip (and only when changed). There is also a setxparams property (not used in the example) that transfers values into the other direction: from the adapter object into the ActiveX component.

The adapter code is quite simple:

package com.softwareag.cis.test40;

import java.util.Date;
import com.softwareag.cis.server.Adapter;
import com.softwareag.cis.util.CDate;

public class ActiveXCalendarAdapter
    extends Adapter
{
    CDate m_date = new CDate(new Date());
    public CDate getDate() { return m_date; }
    public void setDate(CDate value) { m_date = value; }

    String m_adapterDay;
    public String getAdapterDay() { return m_adapterDay; }
    public void setAdapterDay(String value) { m_adapterDay = value; }

    String m_adapterMonth;
    public String getAdapterMonth() { return m_adapterMonth; }
    public void setAdapterMonth(String value) { m_adapterMonth = value; }

    String m_selectedDate;
    public String getSelectedDate() { return m_selectedDate; }
    public void setSelectedDate(String value) { m_selectedDate = value; }

    String m_adapterYear;
    public String getAdapterYear() { return m_adapterYear; }
    public void setAdapterYear(String value) { m_adapterYear = value; }

    public void onGetDate()
    {
        String day = m_adapterDay;
        if (day.length() == 1) day = "0" + day;
        String month = m_adapterMonth;
        if (month.length() == 1) month = "0" + month;
        m_date.setDate(m_adapterYear+month+day);
    }
}

The adapter's properties are automatically filled. The onGetDate() method assembles the properties to form a Application Designer date.

Properties

www.softwareag.com

Copyright © 2005-2014 Software AG, Darmstadt, Germany.

SEARCH   CONTENTS   |   PDF BOOKS   |   HOME   UP   PREV   NEXT