September 2010 - Visual DataFlex 2010/v16 released
|
|
|
VDF 2010/V16 released
The summer period has seen Data Access very busy with releases of Visual DataFlex, the AJAX Framework and Visual Report writer. We have also noticed a useful looking Crystal related MassVerify tool that may be of of interest to Visual DataFlex Users
Codejock based Grid Classes
As has been highlighted in earlier newsletters, the major new feature is the extra programmer and end user control provided by the new Codejock based list and data entry classes. See below, and the report of our June VDF SIG meeting for more on these.
The grid provides new levels of control over the behaviour and functionality of Windows application grids. And the results are great-looking too. The grid’s set of capabilities can make your applications more competitive in the marketplace and more satisfying to customers.
Compared with the current grid, the new Visual DataFlex 2010/16.0 grid will provide developers with many new grid features such as strong in-cell text editing capability and improved performance especially with large data sets.
VDF developers now have state of the art data entry and data list controls which will have a major impact on your applications!
|
|
Special offer- Discovering Visual DataFlex
 Purchase VDF 2010/V16 at £500 before the end of September 2010 and get a free copy of "Discovering Visual DataFlex", the definitive training VDF training manual. This will include a free addendum covering the VDF 2010/V16 changes as soon as it is available.
This high quality, full-colour, 680-page guide will tell you all about the Visual DataFlex language, the main tools used for building applications (Studio, Database Builder and Database Explorer), the role of Data Dictionaries, Object Oriented Programming, and the Reporting features included in the software suite.
Discovering Visual DataFlex teaches you how to build full-scale Windows applications through the use of examples, exercises and software.
Free VDF Personal Edition
AJAX Framework
VDF as a web application development tool continues to evolve with the latest AJAX Framework V2.2. Visual DataFlex gives you the opportunity to develop web applications that are way ahead of the usual "submit and see how many errors you get" style of so many web "applications". With Visual DataFlex you get the best of both (Windows & Web) worlds and with a common code base for both, making application development much faster and maintenance much easier with just one set of data processing and data entry rules to maintain. More details below.
Training
VDF with SQL Databases - 1 day training day
We have had this subject waiting for a date for a while now - and we already have three provisional bookings!
Date:- Thursday 18 November
Venue:- Asckey Data Services Ltd
Cost:- Free - this is a "VDF SIG" day
For an overview of this, see our details below
Please email us - sales@asckey.com if you would be interested.
New VDF 2010/v16 grid Classes - 1 day training day
We are looking to repeat this training day in the Autumn, now that VDF 2010/v16 is released, if there is sufficient interest. Email sales@asckey.com if you would be interested.
Date:- Thursday 2 December
Venue:- Asckey Data Services Ltd
Cost:- £100 to include lunch
Please email us -
Back to Top
|
| VDF 2010/V16 - Highlights
The new Grid and List classes
These are the major feature of VDF 2010/V16. They provide much greater control for the programmer in loading and processing data, and you can give much more control to the application user who can take charge of which columns to show, changing the ordering of data records, and even the appearance via skinning. If you let them of course.
These screen shots show just how much of an improvement these can be. This is the new Grid class with two columns pulled out to provide grouping.
And this is the report preview derived from that
Remember, any layout a user sets is remembered for them (if you do not disable that capability) when they come back into the application.
Users - once they realise they can do all this - love it, because it is so simple and visual. This can be a useful alternative to providing for the inevitable multiple variations of layout, sorting, etc for some of the minor reports that users request, normally built with more elaborate reporting tools. Just provide an interactive list and let the user get on with it!
No comparison!
|
| The VDF AJAX Library - V2.2
"AJAX" is the name given to a group of interrelated web development techniques used on the client-side to create interactive web applications.
 Visual DataFlex provides an extensive AJAX Framework which enables and short cuts the development of interactive, feature rich and user friendly web applications. Of great significance is the fact that the VDF AJAX library accesses the business rules layer of your Windows Visual DataFlex applications, automatically defining data entry validations, control of look up lists, and control of the data processing that must occur when editing and saving data. This means that with Visual DataFlex you can build better web applications faster!
New features in this release include:
- Improved appearance with updated themes - Both the ’classic’ and ’business’ themes are updated with new icons, buttons and other improvements to visual appeal and improving the loading speed, reducing the amount of flicker by using sprite techniques when loading pages.
- Your VDF developed web applications inherently look good and perform well
- Expressions - the new expression data binding allows you to directly call functions in your Visual DataFlex application that will be executed to show a calculated value at the client side (HTML). For example: <span vdfDatabinding="e:CalcAmount" /> where CalcAmount is the name of a published function at the Visual DataFlex Server side that should perform the calculation and return the result.
- New VdfCall API - At some point you will want to call a function in your Visual DataFlex application directly from the browser. Now you can do that very easily using the new VdfCall interface. You can make those AJAX calls to the server within a single line of code, passing function name, the parameters as an array, and a reference to
-
The more code that can be developed inside VDF the simpler it will be to maintain, the more secure the application will be, and the faster it will run. This new call allows you to move more application code to the server side Web Application as opposed to creating it in the ASP code or even less desirable, client side browser.
- Data bound server call - One of the difficulties when making AJAX calls to the server is that the AJAX calls are stateless, meaning that each call should contain all the information the server needs to perform the operation. Similar to the VdfCall above, but the data bound call makes sure that all buffers at the server side contain the records that are currently active at the client, making it easy to work with the buffers. Buffer values that are changed at the server side during the call will be shown upon return of the call.
- The VDF AJAX library is continually evolving to make development easier, reducing your need to handle detail and allowing you to concentrate on your application functionality. Context, which statelessness implies is lost, is everything to a running application. This class preserves context for you, enabling functions to be inherently more sensitive and data aware without you needing to take this into account. Getting closer and closer to what we take for granted in a Windows application in fact.
- Runtime labels. This new call allows an application to easily get the server side data dictionary label for a field. For example: <span vdfControlType="vdf.core.Label" vdfDataBinding="customer.name" />.
- Improved DDO Structure support. The way the information from the data dictionaries between the client side and server side is exchanged has been redesigned to be able to handle more complex database forms.
- Means less work to do to keep complexity under control
- Error details & CollapsePanel Errors now have a "details" section that will show error details. By default the details are hidden. This allows for more user friendly messages for the end-user while still providing as much as possible detail for the developer.
- Good error detail helps you when supporting your applications, but best not to overload the user with detail unless needed for support purposes.
 The AJAX Library is included with Visual DataFlex and enables developers to make their web applications more feature-rich and better looking. It includes both the foundation for building AJAX (or Web 2.0 applications), as well as a sample application that shows the developer how to do it.
|
VRW was fully released in July, and a new build will be available specifically to work with Visual DataFlex v16 soon after the release of that.
We were involved in pre-release testing, so it may be of interest to see what our technical staff had to say about the product.
The application is clearly laid out and I was able to find most of what I was looking for.
The integration class was easily added to the project and a simple report view can be generated very quickly using the wizard provided.
The wizard itself was clear and easy to understand and surprisingly only took less than a minute to get the report view integrated and working complete with some selection criteria.
The ability to easily configure the preview panel was found to be a particularly useful feature which is not available in other reporting tools.
VRW provides a nice and simple entry level tool to create reports within a Visual DataFlex environment.
At a cost which is significantly below that of Crystal Reports for DataFlex, any new VDF developer will find Visual Report Writer worth looking at for building the inevitable collection of reports that need to accompany a Visual DataFlex end user application.
Back to Top
|
VDF Training
Using SQL Server for real - 18/11/2010
Running VDF with server databases has been possible for well over ten years, and is now becoming standard practice, especially with the "Express", no cost versions of the major databases.
We will be putting on a one day course going into some depth on using SQL Server based on our experiences when converting our Eclipse-fm® system to MS SQL Server.
Going beyond the simple database conversion you can get huge performance benefits with embedded SQL, but you can also fall into big holes if you don’t know some of the SQL tricks!
Outline content
Introduction
What makes server databases so imperative?
A basic "as is" conversion
- What problems might you run into (date/time, orphans, .....?)
- How much re-coding is necessary (99.9% of the time, none!)
Installation and management.
- The minimum of what you can survive with if nothing but a VDF database converted as is.
- Other SQL Server management tools and where to get them
Starting to use the database
- Roll back - atomic transactions
- Benefits, code changes needed
Making Selections at the server
- Limitations of VDF code
- Introduction to Embedded SQL
Advanced SQL - what you could do
An "ideas" session, not detailed hands on instruction, and based on some of our application development. Including using SQL in Codejock Grids which can speed up loading selected records from large databases by a factor of ten or more.
What you will need
Apart from the last session, this will be hands on, so you will need to come with a PC with VDF on it (make it V16, why not?!), and MS SQL Express (or the full version). Get the SQL Express version from http://www.microsoft.com/express/database/
We have some interest expressed in this already, and numbers are limited, so please let us know soon if you would be interested.
Date:- Thursday 18 November
Venue:- Asckey Data Services Ltd
Cost:- Free! This is a VDF SIG training day.
|
Working with the new Grids
The Problem:
We have an application that needs to incorporate the functionality of a particular spreadsheet, but the spreadsheet shows each transaction as a column, the field headings are many, and most are quite long.
To accommodate this, we need data presented as a grid that allows entry in a similar style to a spreadsheet with the Data Column Headings down the left hand side, each Data Row (database record) being represented as a Grid Column.
The new VDF 16 cCJGrid class allows us to do this much more easily that the old Grid class.
Here is why:
- The cCJGrid uses a ‘Data Source’ which is a Struct Array that you can easily control.
- We can make the grid look much nicer by skinning it, for example to look like an Office 2007 control.
- Properties of the cCJGrid allow us to provide that navigation (by Mouse or Keyboard) allows data entry “in situ”, or only when the cell is ‘Clicked’.
- Although we used a non data aware grid class, adding data aware capabilities (i.e. awareness of the Data Dictionary business rules) to the control was relatively easy.
- Formatting cells is so much easier, and the results look much better that the old Grid.
- The cCJGrid allows us to ‘Freeze’ columns, so they are always visible – in this case providing the fixed row titles.
- Transposing the data to be Vertical, rather than Horizontal was relatively easy using the Struct Arrays.
- The cherry on the icing is that the cCJGrid class is based on the cCJReportControl, and that means showing a preview or printing the content was so easy.
This is what we needed to do:
- Create some properties which define things like the ‘Server’ and ‘Main File’ for the Grid.
- The ‘Data Source’ for the new grid classes is a Struct Array and we used a second Struct Array to represent the Columns and Rows of the data table. This second Struct Array is used to Get the data when populating the Grid, and to determine if Cell values have changed when Saving the data (using the Server DDO, which ensures all the business rules are observed).
- The ‘Rows’ are defined by a method which sets another Struct Array Property. Crucially, this contains attributes that determine formatting and validation for that field (which can include Justification, Masking and Colour), allowing us to control the appearance in far more detail than was possible with the old style grids.
- When adding a record, set the default values from the Server DDO.
- Masking for the ‘Row’ can be applied when navigating out of a cell, so an entry ‘01092010’ would be formatted as ‘01/09/2010’. This is not native behaviour, but wasn’t hard to code.
- Add a Context Menu to allow various actions on Right Click (such as Print Preview).
Finally, a screen shot:
Note that the number of columns is unlimited, as these are of course records! The number of rows is fixed, as these are the data fields that we selected to use from the data file.
Back to Top
|
 A Useful Crystal Reports Tool?
Do you use and/or supply Crystal reports alongside VDF?
If the data file a report uses changes, then you will have to re-verify every report that uses that file. Similarly if the location of reports changes, as may be the case where you develop a system for a client, each report will have to be re-connected to the (changed location of the) data source.
Redeemed Software, a Visual DataFlex developer has created a useful looking "Mass Verify" tool.
Set Mass Verify running and it can verify the reports at a rate of 20 to 30 per minute, dealing with changed data file definitions and changed database connection strings with no further intervention needed.
Mass Verify also has a special feature for Visual Dataflex users who are using the Native Dataflex tables. You can set a connection property for a default data path which can be used to change where Crystal Reports looks for each table. On your development system, you may have your tables located on "C:/Workspaces/Accounting/Data" and your client may have them installed on "G:/Accounting/Data". Mass Verify, can change all your report locations so they match your client’s installation details.
If these problems seem familiar, go look at Redeemed Software’s Mass Verify page and give it a try!
As we have devised our own solutions to such problems we have not tested this utility, so any feedback would be wellcome. But we know that this can be a problem, so the information may be useful to you.
Back to Top
|
| SCANDUC
The Scandinavian DataFlex User Conference
Are you going to SCANDUC?
23. & 24. September 2010
The SCANDUC conferences are aimed at developers using the Visual DataFlex They are hosted by the Scandinavian channel partner Front-IT in association with Data Access Europe and is held every year eighteen months or so at varying locations in Denmark, Norway and Sweden. This year the SCANDUC Conference will be held in Helsingor, a beautiful city in the nothern part of Sealand (a little way north of Copenhagen).
Catch up on the new Grid classes in Visual DataFlex 2010/v16, learn something about building Web applications and deploying Dynamic AI on the iPad, and get a first preview of where Visual Dataflex is going in 2011
Location - Hotel Marienlyst, Helsingor
Full details at http://www.scanduc.com/
|
 Asckey Data Services Ltd is UK Channel partner for Data Access Worldwide, authors of Visual DataFlex. We provide Visual DataFlex, Electos and Dynamic AI sales and support in the UK
Church End Farm
Warboys Road, Pidley,
Cambs, PE28 3DA
0845 2707747
|
|
|
