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DataFlex Web Framework Symposium – Part 9 Extending the Framework with JavaScript

DataFlex Web Framework Symposium – Part 9 Extending the Framework with JavaScript. Stephen W. Meeley Development Team www.dataaccess.com. Goal.

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DataFlex Web Framework Symposium – Part 9 Extending the Framework with JavaScript

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  1. DataFlex Web Framework Symposium – Part 9Extending the Framework with JavaScript Stephen W. Meeley Development Team www.dataaccess.com

  2. Goal • This session will discussthat you can stilldo all the stuff that we’ve spent the last two years shielding you from – but that it’s really complex • Keara [soon to be teenage, daughter]: Well, duh!

  3. Do I (really) need to do this? No! • This is a capability of the Framework that is very valuable to understand exists • It is not a requirement for Web application development

  4. Do I (really) need to do this? • OK, but what do I need to know? • How the Web Framework really works • All those technologies (JavaScript, CSS, HTML and DOM, etc.) • Class construction • Client-side debugging • Harm’s favorite beer…

  5. What is the JavaScript engine? • Runs in the browser • Client-side implementation of the controls • Part of the DataFlex Web Framework • Copied into the AppHTML of your workspace • Included from index.html

  6. Tasks • Renders the user interface • Handles user interface events • Communicates with the server • Maintains the application state

  7. Basic Concept Every Web Object in DataFlex has a corresponding JavaScript object. DataFlex classes have corresponding JavaScript classes. 1 to 1 relationship

  8. Components of a Control • DataFlex Class Package • AppSrc (workspace) • Defines server-side interface (methods and properties) • JavaScript Class • AppHTML (workspace) • Defines the client-side interface • Renders the user interface • Handles user interface events • Communicates with the server • CSS • AppHTML (workspace)

  9. df.WebObject • Core of the JavaScript engine • Web Properties • Server Actions Extending Web Framework Applications

  10. df.WebBaseUIObject • Basic rendering functionality • Calls methods needed for rendering • Defines main rendering API Extending Web Framework Applications

  11. df.WebBaseControl • Basic control • Control API (used by the containers) • Positioning within column layout Extending Web Framework Applications

  12. Media Control • Relatively simple - very specific task / use • cDJCase.pkg – in AppSrc • cWebBaseControl • Construct_Object • Define web properties (including local data) • Configure class / superclass (ms.DJCase) • Define methods • AddItem • ShowItems ClientAction “fill” • OnSelect • DJCase.css – in AppHTML\Custom • Sizes, colors, allignment, etc.

  13. Media Control • DJCase.js – in AppHTML\Custom • df.WebBaseControl • Constructor • Define synchronization • Define methods • Openhtml • Closehtml • Afterrender • Client-action fill • Renderlps • Onclick • Selectitem

  14. Slider Case Study • Complex – generalized use increases complexity • Defined need • Examined options • Used “outside” resource for JavaScript • Used “inside” resource for DataFlex • Made adjustments • Data and non-data aware • Overall behaviors • Styled – including multiple themes

  15. Slider • cWebSlider.pkg • cWebBaseDEO • Construct_Object • Define web properties (including local data) • Configure class / superclass (df.WebSlider) • Define methods • AddLabel • OnFillLabels • RefillLabels • SerializeObject • ValueToPosition / PositionToValue (data binding) • SetPositionFromValue / SetValueFromPosition • File_Field_Value_Changed • Refresh • UpdateDataBinding

  16. Slider (2) • WebSlider.css • Sizes, colors, alignment, etc. • More complex because it’s part of the Web Framework and needs to be Theme “sensitive” • WebSlider.js – in Lib and included in df-include.js • Lots of stuff I’m not even going to pretend I understand 

  17. We’ve all been here before… • Just another highly-technical capability of the product that few will master but many will use… • Look to the usual suspects… • Examples, documentation, training, Forum discussions, open source projects, gurus-for-hire, etc.

  18. In fact… • By design, we went into depth on many of the topics covered during the Symposium • It’s important to understand that while you can use the product at these technical levels you do not have to • Chances are, if it was a section where you thought “wow, that’s really confusing” – you won’t need to do that 

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