How to create VDF Web Applications

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How to create VDF Web Applications page under construction


Introduction

This page describes the technologies available to create web applictions using Visual DataFlex. It is currently centered around on how to use Active Server pages with VDF.

The overall idea of Active Server pages

ASP is about creating applications that work on the internet in a web browser. To create applications that work in a web browser, then you will need to generate HTML and use a web server (to use Visual DataFlex you will need IIS )

When you have decided to use ASP , then you should try to resist the urge to generate all the HTML from Visual DataFlex. The overall idea of ASP is to integrate your code into HTML in the most efficient manner (E.g. if you have a class called oHTMLWriter then something went wrong!)

The trick is to let your VDF code handle the data and business logic and let ASP handle the HTML presentation.

Getting started

To be able to develop ASP pages , then you need Internet Information Server. The most easy way to get that these days is to grab Microsofts Web Platform installer here :

http://www.microsoft.com/web/channel/products/WebPlatformInstaller.aspx

This tool will provide you with a full stack for developing asp related things. It will also keep track of certain things you need to enable on Windows Vista and Windows Server 2008.

You will also need to install Webapp server from the Portal:Visual DataFlex installer. Note that you will need version 14.1 to support the windows 2008 server.

Putting on your Thinking cap

Grab your Data Dictionaries from your old application and expose these using Web Objects .

  • WBO
  • Global.asa (this is where your code is stackup up. check the list of WBP's there)



In the trenches

Validation

Here are some good links for validating :

Styling using css

Using css for styling can help you if you don't like doing design yourself! If you style using css then somebody else can do the design for you.

Javascript on the client

Javascript can be good for validating what the user enters on the screen. It can also be good for fancy AJAX techniques.