Tag Archives: Properties

EditTables – The Sub-Object Interface

One of the changes we wanted to make with EditTables in v10 was to expose all of their runtime functionality easily through the normal property/method API.  Some of this was already available in previous versions, but usually involved a method to set a plethora of style bits, which is not really satisfactory unless you’re a C++ programmer (as we have been reminded by various developers on several occasions!).

Besides the EditTable as a whole, there are essentially three other main programmable areas:

  1. Columns
  2. Rows
  3. Cells

Providing unique properties and methods to address the capabilities of these areas is not really practicable, as it leads to an “explosion” of property names: For example, accessing the “text” associated with each of these would require three new properties such as:

  • COLUMNTEXT
  • ROWTEXT
  • CELLTEXT

Of course that’s only three, but considering that each of the aforementioned areas has something like 30 properties, you would suddenly add 90+ new property names to the product!  Bear in mind also that columns, rows and cells each have many properties like TEXT in common, so a new name for each of these seems extremely wasteful and unnecessary.

(We could also have used something similar like the existing TEXTBYPOS method to achieve this, but then we’d have 30’ish new “BYPOS” methods instead, and methods aren’t properties anyway).

So, to keep the property namespace under control we decided to use this commonality and implement a set of  “sub-objects” instead, one for each area.  Unsurprisingly these are named:

  • COLUMNS
  • ROWS
  • CELLS  

Each of these sub-objects are indexed and can be used to access a specific column, row or cell in the EditTable.  They all share many common properties and methods, but also expose a few type-specific ones as well.   As an example, this is how to set the CUEBANNER property for each sub-object:

ctrlEntID  = @window : ".EDT_TEST"
cueBanner  = "Test"

// Set the CUEBANNER for the second column
call set_Property( ctrlEntID : ".COLUMNS", "CUEBANNER", cueBanner, 2 )
// Set the CUEBANNER for the third row
call set_Property( ctrlEntID : ".ROWS", "CUEBANNER", cueBanner, 3 )

// Set the CUEBANNER for the cell at column 5, row 7
call set_Property( ctrlEntID : ".CELLS", "CUEBANNER", cueBanner, 5 : @fm : 7 )

// And here's the same using Object Notation Syntax
@ctrlEntID.columns{2}->cueBannner = cueBanner
@ctrlEntID.rows{3}->cueBannner    = cueBanner
@ctrlEntID.cells{5,7}->cueBannner = cueBanner

We’ll take a look at each of these sub-objects in turn over the next few posts to examine their functionality in more detail.

 

EditTables – The new “CELL” events

The OpenInsight EditTable has always supported a set of cell-related common events that are fired when a user interacts with the control:

  • CHAR
  • CHANGED
  • CLICK
  • DBLCLK
  • OPTIONS

In order to process these events properly however, it is necessary to know which cell they relate to, and this can ostensibly be found by using the NOTIFYPOS property, which is set to the position of the cell that raised the event.

In theory this approach works well, but in practice it can exhibit problems:  Events in OpenInsight are nearly always raised in an asynchronous fashion, which means that if two of those events where executed in quick succession for different cells, then NOTIFYPOS could be set to the position of the second cell, before the Basic+ event handler could process the event for the first cell, thereby leading to incorrect results.

In order to handle this better the EditTable now supports a series of corresponding “CELL” events:

  • CELLCHAR
  • CELLCHANGED
  • CELLCLICK
  • CELLDBLCLK
  • CELLOPTIONS

The only difference here is that these events pass the indexes of the cell that raised them as arguments to the event handler, thereby preserving their origin accurately.

E.g. The signature for the old CHANGED event looks like this:

Function Changed( CtrlEntID, CtrlClassID, NewData )

Whilst the signature for the CELLCHANGED event looks like this:

Function CellChanged( CtrlEntID, CtrlClassID, ColNum, RowNum, NewData )

Note that when a “CELL” event is defined the EditTable will non longer raise the ordinary event to prevent the notification from being processed twice.

(One useful example of the benefits of having the “CELL” events is that you can now use the new CELLCHANGED event for cell validation, rather than the usual POSCHANGED event, due to the fact that you know precisely where the change originated from. You also know that there actually was a change, rather than having to compare the cell’s current contents to it’s GOTFOCUSVALUE to discover this).

 

 

 

EditTables – Deleting and Inserting Rows

Support for deleting and inserting rows in the EditTable control has always been somewhat basic, exposing only minimum functionality that allows you to control how a user inserts or deletes a row in the grid.  We’ve enhanced this for version 10 by providing some fine-grain control over the row insertion and deletion process that we’ll describe below.

Imposing limits

Firstly, a couple of new properties have been implemented that allow you to set limits on the number of rows a user can add or remove from the EditTable via the keyboard: These are the MAXROWLIMIT and MINROWLIMIT properties.

MAXROWLIMIT property

When MAXROWLIMIT is set the user cannot use the Insert key to insert more rows than the number specified by this property.  The default value is “0”, which means there is no maximum limit.   Note that this property does not apply to programmatic INSERT method operations or data set by the LIST or ARRAY properties.

MINROWLIMIT property

When MINROWLIMIT is set the user cannot use the Delete key to delete EditTable rows once the minimum limit has been reached. The default value is “0”, which means there is no minimum row limit.   Note that this property does not apply to programmatic DELETE method operations or data set by the LIST or ARRAY properties.

Blocking the “Insert” and “Delete” keys

Previous versions of the EditTable allowed you to set a “Protected” property at design time that stopped all row insert and delete operations by the user.  Unfortunately, this was not actually exposed run-time (unless you adjusted a bit-flag the control’s STYLE property), so in version 10 we’ve expanded the old “Protected” property into two new properties called ALLOWROWDELETE and ALLOWROWINSERT.  These can used at both run-time and design-time.

ALLOWROWDELETE property

When set to False the user cannot use the Delete key to delete rows within an edit table.  The default value of this property is True.

ALLOWROWINSERT property

When set to False the user cannot use the Insert key to insert new rows within an edit table.  The default value of this property is True.

Managing the “Insert” and “Delete” keys

Finally, we made some changes to the way the actual inserts and deletes take place to give you an opportunity to intercept them for even more control.  In previous versions of OpenInsight the EditTable notified you of an insert or delete operation after it had taken place, via the INSERTROW and DELETEROW events respectively.  This means that if you wanted to ‘prevent’ the modification based on some run-time criteria you had to effectively undo it, which usually included some sort of unpleasant visual effect as the insert or delete was rolled back (it also resulted in a loss of formatting information or other cell-specific data that you would have to reapply).

In version 10 we’ve added a new Boolean property called ROWEVENTMODE. When set to False (the default) row insertion and deletion via the keyboard behaves in exactly the same way as previous versions of OpenInsight.  When set to True however, the INSERTROW or DELETEROW event happens before the actual operation takes place, and at this point you can do the following:

  1. If you’re using an EventScript you can return FALSE$ and the operation will be cancelled.
  2. If you’re using a code called from a QuickEvent you can set the EventStatus flag in your code to prevent the operation from proceeding further, just as you would currently do in a WINDOW CLOSE event to cancel it.

 

E.g. Stopping a row being deleted in a DELETEROW EventScript handler.

// Assumes "RowEventMode" is "True" 
//
// Check to see if there is anything in column 2 of the deleted data,
// and if so stop the delete via the event return value. 

$insert logical
if bLen( rowData<2> ) then
   // Stop the delete
   retVal = FALSE$
end else
   retVal = TRUE$
end

return retVal

 

E.g. Stopping a row being deleted in a DELETEROW QuickEvent handler

// Assumes "RowEventMode" is "True" 
//
// Check to see if there is anything in column 2 of the deleted data,
// and if so stop the delete via the Event Status 

$insert logical 
if bLen( rowData<2> ) then
   // Stop the delete
   call set_EventStatus( TRUE$ )
end

return

Of course, once you’ve allowed the Insert or Delete operation to take place you may also want to do some post-processing, and for this we’ve provided two new events: INSERTEDROW and DELETEDROW.  These have the same signature as their INSERTROW and DELETEROW counterparts and are executed after the row modification has taken place (Note that these are only fired if the ROWEVENTMODE is True).

It is also worth noting that, as with previous versions of OpenInsight, using the DELETE and INSERT methods to programatically modify the EditTable contents will not trigger the INSERTROW or DELETEROW events (or any subsequent INSERTEDROW and DELETEDROW events either).

The COMMUTERMODULE Property

As most of you will probably know, “commuter module” is the term given to a stored procedure whose main purpose is to handle event processing for a specific form.  Rather than have each individual event processed in a separate event script, quick-events are used instead to call the commuter module directly, passing it various parameters such as the name of the object firing the event, the name of the event itself, and any relevant arguments.  The commuter module then branches off to different internal subroutines to handle the event.

Following this methodology offers several important advantages:

  • Simplified code management
  • Simplified deployment
  • Improved code sharing via internal subroutines
  • Lower memory overhead (single procedure vs. multiple event scripts)

While using a commuter module like this is the recommended way of developing applications in OpenInsight, there has never been any sort of formal link between the commuter module and the form itself, which means that it is usually necessary to adopt a naming convention for this approach to work.

For example, it is common to have a commuter module with the same name as the form, or with the same name as the form and suffixed with the string “_EVENTS”.  By doing this it was easy to define quick-events to call the commuter module in the old v9 Form Designer like so:

v9 Commuter Module Quick Event

v9 Commuter Module Quick Event

The OBJ_CALL_EVENT program looks for a stored procedure with the same name as the form, or one with the same name as the form and suffixed with “_EVENTS”.  It was also possible to avoid the overhead of a lookup and call the commuter module directly by using the “@WINDOW” placeholder like this:

v9 Commuter Module Quick Event (using @WINDOW)

v9 Commuter Module Quick Event (using @WINDOW)

Or the “@WINDOW_EVENTS” placeholder like this:

v9 Commuter Module Quick Event (using @WINDOW_EVENTS)

Of course, even with this approach the form still wasn’t actually linked to it’s commuter module, rather it was only linked to “OBJ_CALL_EVENTS” or a fictitious entity called “@WINDOW”.

In version 10 we’ve added a new WINDOW property called COMMUTERMODULE, which simply contains the name of the stored procedure to use (this can be any valid name – you are no longer limited to one based on the name of the form, though we do suggest you keep this convention to help organize your application):

CommuterModule Property

CommuterModule Property

When the form is saved and compiled this stored procedure is linked to the form with a “used-by” relationship, thereby making deployment easier as you will see the link when you create your RDK definition records.

Another benefit of this is that you can quickly open your commuter module from the form by using the “View Commuter Module” button on the Form Designer toolbar:

View Commuter Module button

View Commuter Module button

Finally you can easily set your quick events to call your commuter module in the Event Designer like so:

Commuter Module QuickEvent

Commuter Module QuickEvent

Note that it uses an “@COMMUTER” placeholder – this is replaced with the contents of the COMMUTERMODULE property at runtime.

(You can still use the previous @WINDOW/_EVENTS or Obj_Call_Events methods if you wish – those options still exist.)

So, this is the first step in tightening the relationship between a form and it’s commuter module.  There is certainly scope for more integration between the two and this is something that we hope to pursue during subsequent releases.

(Disclaimer: This article is based on preliminary information and may be subject to change in the final release version of OpenInsight 10)

Context Menus in OpenInsight 10 – Part I

Using context menus in previous versions of OpenInsight has always been something of a chore: they were not well documented and they were subject to several limitations:

  • They could only be attached to a control programmatically, rather than via the Form Designer.
  • The context menu designer tool would name a menu based on the control it was supposed to be attached to – there was no real concept of sharing a menu between controls.
  • They were limited to a single level – no sub-menu nesting was allowed.
  • They were difficult to modify at runtime.

These issues made them quite onerous to use, which is unfortunate as context menus are an important part of modern UI design, having been in widespread use across the OS since Windows 95.

With version 10 we went back to the drawing board and completely redesigned them to make them first class UI citizens and solve the problems outlined above.

The Context Menu Designer

One of the new tools in the IDE is the Context Menu Designer, which allows you to define the structure of the menu along with any quick events (Event scripts are not supported for context menus).

Context Menu Designer (WIP)

Context Menu Designer (WIP)

Menus saved by the designer are given simple names in the same format as any other repository entity – they are no longer based on the name of a specific control.  They can then be attached in the Form Designer by using an object’s CONTEXTMENU property.

(Note that like normal WINDOW menus they also support nested structures as they share the same code-base.)

The CONTEXTMENU property

Forms and controls now support an explicit CONTEXTMENU property which is the repository ID of a saved context menu.

ContextMenu Property

ContextMenu Property

At runtime, when a user right-clicks on a control, the Presentation Server looks at the CONTEXTMENU property to find the name of an attached menu, and, if found, displays it.

When the user selects an item from context menu a MENU event is raised and sent to the quick event target defined in the designer.

This is a much simpler and streamlined process.

Of course, that’s not the end of the story as there are times when the context menu will need to be adjusted before it is displayed at runtime, depending on factors like the state of it’s parent control and so on.  We’ll take a look at how to do that in the next post.

(Disclaimer: This article is based on preliminary information and may be subject to change in the final release version of OpenInsight 10).

The FILEPREVIEW control

One of the new controls added to version 10 is the FILEPREVIEW control, which taps into the Windows Shell interface to expose the same  functionality provided by the Windows Explorer when previewing the contents of files, as per the example below:

explorer_preview

Windows Explorer PowerPoint preview

Using the FILEPREVIEW control is quite easy – simply set the FILENAME property with the name and path of the file you want to preview, and if the OS has handlers installed for that file type then the control will render them.

Here’s an example of previewing a PowerPoint file:

  fileName = get_Property( @window : ".EDL_FILENAME", "TEXT" )
  if bLen( fileName ) then
     call set_Property_Only( @window : ".FPV_VIEWER", "FILENAME", |
                             fileName )
  end
filepreview

FILEPREVIEW control example

The devil of course is in the details – your OS must have the correct handler DLLs installed for you to view the preview of the file, and this may rely on third party software being installed as well.  For example, to preview Word and Excel documents you must have Office installed, to preview PDF files you must have something like Adobe Reader installed and so on.  You can test for this at runtime by using the PREVIEWHANDLER method, which returns a GUID identifying the preview handler DLL if it is installed.  You simply pass the extension you wish to look up and check for a returned GUID like so:

  handlerGUID = exec_Method( previewCtrl, "PREVIEWHANDLER", "pdf" )
  if bLen( handlerGUID ) then
    // We have a PDF preview viewer on the workstation ...
    call set_Property_Only( previewCtrl, "FILENAME", "c:\temp\test.pdf" )
  end 

The control also supports an ACTIVE property which returns TRUE$ if the control currently has a file loaded for previewing.

(Disclaimer: This article is based on preliminary information and may be subject to change in the final release version of OpenInsight 10).

 

 

The AUTODROPDOWN property

One of the areas in which dropdown comboboxes have always been lacking is the ability to fully control when the list is populated in a visually pleasing manner.  Under most circumstances the contents are loaded well before the dropdown button is clicked, and this is fine, but in situations where the items are context -sensitive it is necessary to load them just before the list is shown, and in previous versions this can look a little messy.

You can see an example of this in the OI9 System Editor++: there is a very handy pair of dropdowns at the top if the form that allow you to navigate your source code using inserts and labels, but when you use them you see the list contents loaded just after it has been dropped; this looks somewhat jarring and usually causes issues with the vertical scrollbar too.

Of course, the reason for this is that OpenInsight events are normally fired in an asynchronous manner, and the DROPDOWN event won’t run until after the list has been shown.  While you do have the ability to fire events in a synchronous fashion, this can introduce other complications and is something that should be avoided whenever possible.

So, in order to fix this, OpenInsight 10 provides a new property called AUTODROPDOWN that allows the list to be loaded during the DROPDOWN event and then displayed precisely when needed.

AUTODROPDOWN is a boolean property and is set to TRUE$ by default.

  • When set to TRUE$ the combobox behaves in exactly the same way as previous versions.
  • When set to FALSE$, the list is not shown until you explicitly set the DROPDOWN property to TRUE$. This gives you ability to load the list contents and then show them when ready.

Here’s an example of loading a list of STPROC repository items in a DROPDOWN event when AUTODROPDOWN is FALSE$

  // Get a list of items
  reposIDs = get_Repos_Entities( "", "STPROC", "", FALSE$, |
                                 TRUE$, FALSE$, "" )
  
  // Load them into the combobox LIST property
  call set_Property_Only( ctrlEntID, "LIST", reposIDs )

  // Now show the list
  call set_Property_Only( ctrlEntID, "DROPDOWN", TRUE$ )

Comboboxes as options buttons?

Another area where AUTODROPDOWN may help is for systems that use comboboxes as a combined edit and options control, where clicking the dropdown button loads a dialog box or popup instead of dropping a list.  Again, in previous versions this tends to look a little crude because the combobox shows a very shallow list even though it is empty, but with AUTODROPDOWN set to FALSE$ the list is never shown, and consequently looks much better.

(Disclaimer: This article is based on preliminary information and may be subject to change in the final release version of OpenInsight 10).