Tag Archives: Properties

The Set_Property_Only subroutine

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One of the problems with the existing Set_Property function is that it also performs an implicit Get_Property operation to return the previous contents of the property to the caller.  In many cases this information is simply discarded after the “Set” making the “Get” call actually unnecessary, and this inefficiency goes unnoticed as the quantity of information retrieved during the “Get” is small.  However, in some cases the effect is noticeable: For example, setting the ARRAY property of an EditTable that contains several thousand rows to null (i.e. clearing it), will produce a noticeable delay while the ARRAY contents are accessed and returned.

A new subroutine, called Set_Property_Only, has been added to the OpenInsight 10.  This operates in the same way as the existing Set_Property function except for the fact that it doesn’t bother performing a Get_Property operation to return the previous property contents to the caller.  This helps you to optimize your code for better performance.

The new FILESYSTEM object

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As we mentioned earlier the decision was taken to deprecate the Utility function, but we still needed to provide the equivalent functionality by some other means. The obvious candidate to update here was the existing SYSTEM object, but rather than overloading it with a whole raft of new members, all of which were filing-system related, we took the decision to create a new object instead, and thus the FILESYSTEM object was born.

The FILESYSTEM object, like the SYSTEM one, is managed internally by the Presentation Server and simply exposes some common Windows Shell directory and file-based functionality to Basic+. As you’ll see below there are some new properties and methods that were not part of the old Utility function, but we’ve also taken the opportunity to enhance some of the existing methods as well – they now hook into the Windows API SHFileOperation function thereby offering better system integration, such as using standard Windows copy/move dialogs and exposing “Undo” functionality.

Here’s a summary of the FILESYSTEM object interface that you’ll find in the new version:

Properties

Property Dev Run Get Set Description
CURRENTDIR X X X Provides access to the current working directory.
DRIVELIST X X Returns a dynamic array of attached drive letters.
FILEOPRESULT X X Returns the most recent result code from a FILESYSTEM object method call.
SYSTEMDIR X X Returns the OS System directory.
TEMPDIR X X Returns the user’s Temp directory.
WINDOWSDIR X X Returns the Windows directory.

Methods

Method Description
COPYDIR Copies an entire directory and sub-directories to a new location.
COPYFILES Copies one or more files to a new location.
DELETEFILES Deletes one or more files.
DIREXISTS Checks to see if a directory exists.
FILEEXISTS Checks to see if a file exists.
GETABSOLUTEPATH Returns an absolute path from a relative path
GETLONGPATH Converts a short path to its long path form
GETRELATIVEPATH Returns a relative path from an absolute path
GETSHORTPATH Converts a long path to its short path (i.e. MS-DOS “8.3”) form
GETSPECIALDIR Returns the path to a “special” OS folder such as “My Documents”, AppData and so on.
MAKEDIR Creates a directory or nested directory path.
MOVEDIR Moves an entire directory and sub-directories to a new location.
MOVEFILES Moves one or more files to a new location.
REMOVEDIR Removes a directory.
RENAMEDIR Renames a directory.
RENAMEFILE Renames a file.

Of course this is probably not a final list, so please feel free to leave us a comment if you think of anything that would make a good addition here.

The SYSTEM object – some new properties

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As the project moves along and work progresses you should see many new items added to the object interfaces in the Presentation Server. One of the main reasons for this is to try and reduce the amount of times you as a developer have to call the Windows API directly – we realize that most OI programmers aren’t C programmers and so we’re trying to save you the pain of dealing with static data types, C-structures and pointers wherever possible.

In light of this we’ve made some changes to the SYSTEM object: As well as bringing across many of the existing Utility services (mentioned previously here) there’s also some brand-new properties and methods too (and we’re not finished yet).

Here’s a quick look at some of the new SYSTEM properties we’ve added so far:

DPI property

This property returns the Windows DPI setting (96, 120 or 144) so you can handle custom scaling in your app if it’s running at a different DPI than the system you designed it on.

ENVVARLIST property

This property returns a list of OS environment variables (just as if you’d typed “set” at the DOS command prompt).

FONTLIST property

This property returns a list of font names that are available on the system.

INTERACTIVE property

This property returns TRUE$ if OpenInsight has been launched in an interactive Windows session (i.e. it has a “desktop”).  It returns FALSE$ if OpenInsight has been launched in a non-interactive session such as from a Windows Service process.

MONITORLIST property

This property returns a dynamic array of monitor information.  Each field in the array contains the following details for each monitor:

  • Monitor Handle
  • Monitor rectangle (left, top, right, bottom)
  • Monitor work area (left, top, right, bottom)
  • Flags
  • Device name.

TYPES property

This property returns a list of the object types that the Presentation Server supports (EDITBOX, LISTBOX, WINDOW and so on).  We’ll cover this in more detail in a later post when we look at some of the properties that expose an object’s type-information to provide a “reflection” interface for the toolset.

That’s just a few of the new additions – we’ll post more as they appear.  If there’s any others you think should be added please leave a comment and tell us.