[Re: Fw: TListBox]

Samuel Liddicott sam at campbellsci.co.uk
Fri Feb 11 08:28:00 EST 2000




> -----Original Message-----
> From: Michal Bukovjan [mailto:mbukovjan at netscape.net]
> Sent: Thursday, February 10, 2000 04:19 PM
> To: lazarus at miraclec.com
> Subject: Re: [Re: Fw: TListBox]
>
>
> Last time I checked the TListBox was working well. I'll look
> why was the
> internal list changed back to TStringList - it makes no sense. The
> TGtkListStringList was created and should be used as a counterpart to
> TListBoxStrings found in Delphi, which looks up the strings
> in the underlying
> Win32 list box. This way, the list box items are not held
> twice in memory.
> Since the TListBoxStrings is Win32 specific, hence the need for
> TGtkListStringList. Note that the TListBox only knows in has
> TStrings, it does
> not now about concrete descendant, which is determined in the
> interface
> object.
>
> The same technique is used for items of TComboBox.

Don't forget this control should save the contents in a real TStringList
during a DestroyHandle, and repopulate the underlying control from this
during the CreateHandle.  When updating the items property, if
HandleAllocated returns false you do the same operations on the temporary
TStringList instead.

One the handle is allocated and populated from the TStringList the
StringList can be free'd.

Sam






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