Understanding How InfoPath Is Different

It might seem odd to name a chapter "InfoPath Is Different," but I suspect that many developers and users of InfoPath form templates and forms will be coming to InfoPath from very different backgrounds. If such developers, for example, attempt to apply to InfoPath assumptions that hold true in other forms environments, they will likely run into problems before too long. Why? Quite simply, InfoPath is different, and to make the best use of it, you need to understand which assumptions that apply to other tools don't apply when using InfoPath, and which limitations of other forms tools InfoPath relieves.

This chapter is intended to provide you with an overall perspective of the characteristics of InfoPath, including several ways in which InfoPath is different from other forms tools. This information is fleshed out by the descriptions and demonstrations of the tasks and technical details described in later chapters in this book.

Some Basic Differences from Other Form Environments

Some InfoPath differences from other form environments are very much in your face, and others are much more subtle.

One of the basic differences between InfoPath and traditional HTML and XHTML forms is that InfoPath does not use a Web browser such as Internet Explorer as its interface. InfoPath 2003 form templates must be filled in using the proprietary InfoPath 2003 client. This approach allows the user access to functionality that is not routinely available in Web browsers but also makes it impractical to use InfoPath in situations where you can't be sure that users have access to a copy of the InfoPath client.

SHOP TALK
THE NEED FOR THE INFOPATH CLIENT

Microsoft's decision to require users to own a copy of the InfoPath 2003 client to be capable of filling in InfoPath forms has some important implications.

The need for the end user to have the InfoPath client effectively rules out InfoPath as a suitable approach for Internet-based form filling. Traditional HTML/XHTML forms or W3C XForms are possible alternative choices. Essentially, if you can't be sure that the end user of the form has the InfoPath client, you probably shouldn't be using InfoPath in your data collection solution. Many newcomers to InfoPath haven't grasped this limitation (it isn't clear from Microsoft's initial marketing materials), and are frustrated when they find that InfoPath 2003 simply isn't a suitable solution for Internet forms.

InfoPath is, however, suitable for many enterprise and intranet/extranet scenarios. If you are using XML widely in your company and can be sure that users have the InfoPath client (many enterprises have corporate licensing), InfoPath should be evaluated seriously as a forms-creation and completion tool.

Less obvious to the new user is just how deeply dependent on XML and its associated technologies the InfoPath 2003 client is.

An XML-Based Forms Tool

InfoPath is an XML-based forms tool. The use of XML has many advantages for developers, some of which are discussed later in this chapter.

Because of its XML foundations, another difference from traditional HTML forms that submit data as name/value pairs is that InfoPath holds and submits data as well- formed XML.

InfoPath Doesn't Use XForms

Around the time that InfoPath 2003 appeared in retail outlets, the World Wide Web Consortium (W3C) finalized the specification of its XML forms technology, XForms. The XForms specification is described fully at http://www.w3.org/TR/xforms. InfoPath 2003 uses several W3C XML technologies ”XPath 1.0, W3C XML Schema 1.0, XSLT 1.0, and so on ”but makes no use of XForms.

XForms is a technology, not a product. XForms can be used, via plugins, in commonly available Web browsers such as Internet Explorer. That means that XForms can be used for XML forms scenarios in which InfoPath might not be suitable because the user does not have access to the InfoPath client to fill in an InfoPath form template.

On the other hand, InfoPath provides a powerful design environment not yet available for XForms at the time of this writing. Similarly, XForms does not, at least in its initial version, provide the database connectivity and XML Web service functionality that InfoPath provides.