Drag and Drop Component Suite Version 4.1
Field test 5, released 16-dec-2001
?1997-2001 Angus Johnson & Anders Melander
http://www.melander.dk/delphi/dragdrop/
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Table of Contents:
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1. Supported platforms
2. Installation
3. Getting started
4. Known problems
5. Support and feedback
6. Bug reports
7. Upgrades and bug fixes
8. Missing in this release
9. New in version 4.x
10. TODO
11. Licence, Copyright and Disclaimer
12. Release history
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1. Supported platforms:
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This release supports Delphi 4-6 and C++ Builder 4-5.
Earlier versions of Delphi and C++ Builder will not be supported. If you need
Delphi 3 or C++ Builder 3 support you will have to revert to version 3.7 of the
Drag and Drop Component Suite.
The library has been tested on NT4 service pack 5 and Windows 2000.
Windows 95, 98, ME and XP should be supported, but has not been tested.
Linux and Kylix are not supported. There are *NO* plans to port the library to
Kylix. The drag and drop protocols available on Linux are too much of a mess at
this time.
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2. Installation:
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1) Before you do anything else, read the "Known problems" section of this
document.
2) Install the source into a directory of your choice.
The files are installed into three directories:
DragDrop
DragDrop\Components
DragDrop\Demo
3) Install and compile the appropriate design time package.
The design time packages are located in the Components directory. Each
version of Delphi and C++ Builder has its own package; DragDropD6.dpk for
Delphi 6, DragDropD5.dpk for Delphi 5, DragDropC5.bpk for C++ Builder 5, etc.
4) Add the Drag and Drop Component Suite components directory to your library
path.
5) Load the demo project group:
demo\dragdrop_delphi.bpg for Delphi 5 and 6
demo\dragdrop_bcb4.bpg for C++ Builder 4
demo\dragdrop_bcb5.bpg for C++ Builder 5
The project group contains all the demo applications.
6) If your version of Delphi does not support text format DFM files (e.g. Delphi
4 doesn't), you will have to use the convert.exe utility supplied with Delphi
to convert all the demo form files to binary format.
A batch file, convert_forms_to delphi_4_format.bat, is supplied in the demo
directory which automates the conversion process.
The C++ Builder demo forms are distributed in binary format.
7) If upgrading from a previous version of the Drag and Drop Component Suite,
please read the document "upgrading_to_v4.txt" before you begin working on
your existing projects.
Note about "Property does not exist" errors:
Since all demos were developed with the latest version of Delphi, most of the
demo forms probably contains references to properties that doesn't exist in
earlier versions of Delphi and C++ Builder. Because of this you will get fatal
run-time errors (e.g. "Error reading blahblahblah: Property does not exist.") if
you attemt to run the demos without fixing this problem. Luckily it is very easy
to make the forms work again; Just open the forms in the IDE, then select
"Ignore All" when the IDE complains that this or that property doesn't exist and
finally save the forms.
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3. Getting started:
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It is recommended that you start by running each of the demo applications and
then look through the demo source. Each demo application is supplied with a
readme.txt file which briefly describes what the demo does and what features
it uses. The demos should be run in the order in which they are listed in the
supplied project group.
Even if you have used previous versions of the Drag and Drop Component Suite it
would be a good idea to have a quick look at the demos. The library has been
completely rewritten and a lot of new features has been added.
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4. Known problems:
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* The Shell Extension components does not support C++ Builder 4.
For some strange reason the components causes a link error.
* There appear to be sporadic problems compiling with C++ Builder 5.
Several user have reported that they occasionally get one or more of the
following compiler errors:
[C++ Error] DragDropFile.hpp(178): E2450 Undefined structure
'_FILEDESCRIPTORW'
[C++ Error] DropSource.hpp(135): E2076 Overloadable operator expected
I have not been able to reproduce these errors, but I believe the following
work around will fix the problem: In the project options of *all* projects
which uses these components, add the following conditional define:
NO_WIN32_LEAN_AND_MEAN
The define *must* be made in the project options. It is not sufficient to
#define it in the source.
If you manage to compile with C++ Builder (any version), I would very much
like to know about it.
* Delphi's and C++ Builder's HWND and THandle types are not compatible.
For this reason it might be nescessary to cast C++ Builder's HWND values to
Delphi's THandle type when a HWND is passed to a function. E.g.:
if (DragDetectPlus(THandle(MyControl->Handle), Point(X, Y))) {
...
}
* Virtual File Stream formats can only be pasted from the clipboard with live
data (i.e. FlushClipboard/OleFlushClipboard hasn't been called on the data
source). This problem affects TFileContentsStreamOnDemandClipboardFormat and
the VirtualFileStream demo.
This is believed to be a bug in the Windows clipboard and a work around hasn't
been found yet.
* Asynchronous targets appears to be broken in the current release.
* When TDropFileTarget.GetDataOnEnter is set to True, the component doesn't work
with WinZip.
Although the file names are received correctly by TDropFileTarget, WinZip
doesn't extract the files and the files thus can't be copied/moved.
This is caused by a quirk in WinZip; Apparently WinZip doesn't like
IDataObject.GetData to be called before IDropTarget.Drop is called.
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5. Support and feedback:
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Since these components are freeware they are also unsupported. You are welcome
to ask for help via email, but I cannot guarantee that I will have time to help
you or even reply to your mail. If you absolytely can't live without my help,
you can alway try bribing me.
You can also try asking for help in the Delphi newsgroups. Since the Drag and
Drop Component Suite is in widespread use, there's a good chance another user
can help you. I recommend the following newsgroups for issues regarding this
library (or COM based Drag/Drop in general):
borland.public.delphi.winapi
borland.public.delphi.thirdparty-tools
borland.public.delphi.oleautomation
borland.public.cppbuilder.winapi
borland.public.cppbuilder.thirdparty-tools
Please choose the most appropiate newsgroup for your question. Do not cross
post to them all. Before posting to the newsgroups, I suggest you try to search
for an answer on the Google (DejaNews) search engine: http://groups.google.com
Chances are that your question has been asked and answered before.
If you have suggestions for improvements please mail them to me:
anders@melander.dk
Please include the words "Drag Drop" in the subject of any email regarding these
components.
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6. Bug reports:
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Bugs can either be reported at my home page (http://www.melander.dk/) or mailed
directly to me: anders@melander.dk.
When reporting a bug, please provide the following information:
* The exact version of the Drag and Drop Component Suite you are using.
* The exact version of Delphi or C++ Builder you are using.
* The name and exact version of your operating system (e.g. NT4 SP5).
* The exact version of the Internet Explorer installed on your system.
If you can provide me with a minimal application which reproduces the problem,
I can almost guarantee that I will be able to fix the problem in very short
time. Please supply only the source files (pas, dfm, dpr, dof, res, etc.) and
mail them as a single zip file. If I need a compiled version I will ask for it.
If you feel you need to send me a screen shot, please send it in GIF or PNG
format.
If you mail a bug report to me, please include the words "Drag Drop" in the
subject of your email.
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7. Upgrades and bug fixes:
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Upgrades can be downloaded from my home page:
http://www.melander.dk/delphi/dragdrop/
Bug fixes will also be posted to the above page.
If you have registered for update notification via the installation program, you
will receive email notification when a new release is available. You will not be
notified of bug fixes.
You can use the installation program to check for and download new releases and
to check for known bugs.
Note: If a new release is made available and you are not notified even though
you registered for notification, you probably mistyped your email address during
installation; About 10% of all registrations supply an invalid email address.
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8. Missing in this release:
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* On-line help has not been updated and included in the kit due to late changes
in the Delphi 6 help system and lack of time.
If time permits, I will update the help and include it in a future release.
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9. New in version 4.x:
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* Completely redesigned and rewritten.
Previous versions of the Drag and Drop Component Suite used a very monolithic
design and flat class hierachy which made it a bit cumbersome to extend the
existing components or implement new ones.
Version 4 is a complete rewrite and redesign, but still maintains
compatibility with previous versions. The new V4 design basically separates
the library into three layers:
1) Clipboard format I/O.
2) Data format conversion and storage.
3) COM Drag/Drop implementation and VCL component interface.
The clipboard format layer is responsible for reading and writing data in
different formats to and from an IDataObject interface. For each different
clipboard format version 4 implements a specialized class which knows exactly
how to interpret the clipboard format. For example the CF_TEXT (plain text)
clipboard format is handled by the TTextClipboardFormat class and the CF_FILE
(file names) clipboard format is handled by the TFileClipboardFormat class.
The data format layer is primarily used to render the different clipboard
formats to and from native Delphi data types. For example the TTextDataFormat
class represents all text based clipboard formats (e.g. TTextClipboardFormat)
as a string while the TFileDataFormat class represents a list of file names
(e.g. TFileClipboardFormat) as a string list.
The conversion between different data- and clipboard formats is handled by the
same Assign/AssignTo mechanism as the VCLs TPersistent employes. This makes it
possible to extend existing data formats with support for new clipboard
formats without modification to the existing classes.
The drag/drop component layer has several tasks; It implements the actual COM
drag/drop functionality (i.e. it implements the IDropSource, IDropTarget and
IDataObject interfaces (along with several other related interfaces)), it
surfaces the data provided by the data format layer as component properties
and it handles the interaction between the whole drag/drop framework and the
users code.
The suite provides a multitude of different components. Most are specialized
for different drag/drop tasks (e.g. the TDropFileTarget and TDropFilesSource
components for drag/drop of files), but some are either more generic, handling
multiple unrelated formats, or simply helper components which are used to
extend the existing components or build new ones.
* Support for Delphi 6.
Version 4.0 was primarily developed on Delphi 6 and then ported back to
previous versions of Delphi and C++ Builder.
* Support for Windows 2000 inter application drag images.
On Windows platforms which supports it, drag images are now displayed when
dragging between applications. Currently only Windows 2000 supports this
feature. On platforms which doesn't support the feature, drag images are only
displayed whithin the source application.
* Support for Windows 2000 asynchronous data transfers.
Asynchronous data tranfers allows the drop source and targets to perform slow
transfers or to transfer large amounts of data without blocking the user
interface while the data is being transfered.
For platforms other than Windows 2000, the new TDropSourceThread class can be
used to provide similar (but more limited) asynchronous data transfer
capabilities.
* Support for optimized and non-optimized move.
When performing drag-move operations, it is now possible to specify if the
target (optimized move) or the source (non-optimized move) is responsible for
deleting the source files.
* Support for delete-on-paste.
When data is cut to the clipboard, it is now possible to defer the deletion of
the source data until the target actually pastes the data. The source is
notified by an event when the target pastes the data.
* Extended clipboard support.
All formats and components (both source and target) now support clipboard
operations (copy/cut/paste) and the VCL clipboard object.
* Support for shell drop handlers.
The new TDropHandler component can be used to write drop handler shell
extensions. A drop handler is a shell extension which is executed when a user
drags and drops one or more files on a file associated wth your application.
* Support for shell drag drop handlers.
The new TDragDropHandler component can be used to write drag drop handler
shell extensions. A drag drop handler is a shell extension which can extend
the popup menu which is displayed when a user drag and drops files with the
right mouse button.
* Support for shell context menu handlers.
The new TDropContextMenu component can be used to write context menu handler
shell extensions. A context menu handler is a shell extension which can extend
the popup menu which is displayed when a user right-clicks a file in the
shell.
* Drop sources can receive data from drop targets.
It is now possible for drop targets to write data back to the drop source.
This is used to support optimized-move, delete-on-paste and inter application
drag images.
* Automatic re-registration of targets when the target window handle is
recreated.
In previous versions, target controls would loose their ability to accept
drops when their window handles were recreated by the VCL (e.g. when changing
the border style or docking a form). This is no longer a problem.
* Support for run-time definition of custom data formats.
You can now add support for new clipboard formats without custom components.
* Support for design-time extension of existing source and target components.
Using the new TDataFormatAdapter component it is now possible to mix and match
data formats and source and target components at design time. E.g. the
TDropFileTarget component can be extended with URL support.
* It is now possible to completely customize the target auto-scroll feature.
Auto scroling can now be completely customized via the OnDragEnter,
OnDragOver, OnGetDropEffect and OnScroll events and the public NoScrollZone
and published AutoScroll properties.
* Multiple target controls per drop target component.
In previous versions you had to use one drop target component per target
control. With version 4, each drop target component can handle any number of
target controls.
* It is now possible to specify the target control at design time.
A published Target property has been added to the drop target components.
* Includes 20 components:
- TDropFileSource and TDropFileTarget
Used for drag and drop of files. Supports recycle bin and PIDLs.
- TDropTextSource and TDropTextTarget
Used for drag and drop of text.
- TDropBMPSource and TDropBMPTarget
Used for drag and drop of bitmaps.
- TDropPIDLSource and TDropPIDLTarget
Used for drag and drop of PIDLs in native format.
- TDropURLSource and TDropURLTarget
Used for drag and drop of internet shortcuts.
- TDropDummyTarget
Used to provide drag/drop cursor feedback for controls which aren't
registered as drop targets.
- TDropComboTarget (new)
Swiss-army-knife target. Accepts text, files, bitmaps, meta files, URLs and
file contents.
- TDropMetaFileTarget (new)
Target which can accept meta files and enhanced meta files.
- TDropImageTarget (new)
Target which can accept bitmaps, DIBs, meta files and enhanced meta files.
- TDragDropHandler (new)
Used to implement Drag Drop Handler shell extensions.
- TDropHandler (new)
Used to implement Shell Drop Handler shell extensions.
- TDragDropContext (new)
Used to implement Shell Context Menu Handler shell extensions.
- TDataFormatAdapter (new)
Extends the standard source and target components with support for extra
data formats. An alternative to TDropComboTarget.
- TDropEmptySource and TDropEmptyTarget (new)
Target and source components which doesn't support any formats, but can be
extended with TDataFormatAdapter components.
* Supports 27 standard clipboard formats:
Text formats:
- CF_TEXT (plain text)
- CF_UNICODETEXT (Unicode text)
- CF_OEMTEXT (Text in the OEM characterset)
- CF_LOCALE (Locale specification)
- 'Rich Text Format' (RTF text)
- 'CSV' (Tabular spreadsheet text)
File formats:
- CF_HDROP (list of file names)
- CF_FILEGROUPDESCRIPTOR, CF_FILEGROUPDESCRIPTORW and CF_FILECONTENTS (list of
files and their attributes and content).
- 'Shell IDList Array' (PIDLs)
- 'FileName' and 'FileNameW' (single filename, used for 16 bit compatibility).
- 'FileNameMap' and 'FileNameMapW' (used to rename files, usually when
dragging from the recycle bin)
Image formats:
- CF_BITMAP (Windows bitmap)
- CF_DIB (Device Independant Bitmap)
- CF_METAFILEPICT (Windows MetaFile)
- CF_ENHMETAFILE (Enhanced Metafile)
- CF_PALETTE (Bitmap palette)
Internet formats:
- 'UniformResourceLocator' and 'UniformResourceLocatorW' (Internet shortcut)
- 'Netscape Bookmark' (Netscape bookmark/URL)
- 'Netscape Image Format' (Netscape image/URL)
- '+//ISBN 1-887687-00-9::versit::PDI//vCard' (V-Card)
- 'HTML Format' (HTML text)
- 'Internet Message (rfc822/rfc1522)' (E-mail message in RFC822 format)
Misc. formats:
- CF_PREFERREDDROPEFFECT and CF_PASTESUCCEEDED (mostly used by clipboard)
- CF_PERFORMEDDROPEFFECT and CF_LOGICALPERFORMEDDROPEFFECT (mostly used for
optimized-move)
- 'InShellDragLoop' (used by Windows shell)
- 'TargetCLSID' (Mostly used when dragging to recycle-bin)
* New source events:
- OnGetData: Fired when the target requests data.
- OnSetData: Fired when the target writes data back to the source.
- OnPaste: Fired when the target pastes data which the source has placed on
the clipboard.
- OnAfterDrop: Fired after the drag/drop operation has completed.
* New target events:
- OnScroll: Fires when the target component is about to perform auto-scroll on
the target control.
- OnAcceptFormat: Fires when the target component needs to determine if it
will accept a given data format. Only surfaced in the TDropComboTarget
component.
* 8 new demo applications, 19 in total.
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10. TODO (may or may not be implemented):
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* Async target demo (with and without IAsyncOperation support).
* Scrap file demo.
* Native Outlook message format.
* Structured storage support (IStorage encapsulation).
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11. Licence, Copyright and Disclaimer:
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The Drag and Drop Component Suite is Copyright ?1997-2001 Angus Johnson and
Anders Melander.
All rights reserved.
The software is copyrighted as noted above. It may be freely copied, modified,
and redistributed, provided that the copyright notice(s) is preserved on all
copies.
The Drag and Drop Component Suite is freeware and we would like it to remain so.
This means that it may not be bundled with commercial libraries or sold as
shareware. You are welcome to use it in commercial and shareware applications
providing you do not charge for the functionality provided by the Drag and Drop
Component Suite.
There is no warranty or other guarantee of fitness for this software, it is
provided solely "as is".
You are welcome to use the source to make your own modified components, and such
modified components may be distributed by you or others if you include credits
to the original components, and do not charge anything for your modified
components.
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12. Version 4 release history:
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16-dec-2001
* Ported to C++ Builder 4.
* Released for test as v4.1 FT5.
12-dec-2001
* Fixed C++ Builder name clash between TDropComboTarget.GetMetaFile and the
GetMetaFile #define in wingdi.h
1-dec-2001
* The IAsyncOperation interface is now also declared as IAsyncOperation2 and
all references to IAsyncOperation has been replaced with IAsyncOperation2.
This was done to work around a bug in C++ Builder.
Thanks to Jonathan Arnold for all his help with getting the components to
work with C++ Builder. Without Jonathan's help version 4.1 would prabably
have shipped witout C++ Builder support and certainly without any C++
Builder demos.
* Demo applications for C++ Builder.
The C++ Builder demos were contributed by Jonathan Arnold.
27-nov-2001
* TCustomDropTarget.Droptypes property renamed to DropTypes (notice the case).
Thanks to Krystian Brazulewicz for spotting this.
24-nov-2001
* The GetURLFromString function in the DragDropInternet unit has been made
public due to user request.
21-nov-2001
* Modified MakeHTML function to comply with Microsoft's description of the
CF_HTML clipboard format.
* Added MakeTextFromHTML function to convert CF_HTML data to plain HTML.
Provides the reverse functionality of MakeHTML.
* Added HTML support to TTextDataFormat class and TDropTextSource and
TDropTextTarget components.
* Fixed C++ Builder 5 problem with IAsyncOperation.
* Released for test as v4.1 FT4.
10-nov-2001
* Added NetscapeDemo demo application.
Demonstrates how to receive messages dropped from Netscape.
This demo was sponsored by ThoughtShare Communications Inc.
* Released for test as v4.1 FT3.
23-oct-2001
* Conversion priority of TURLDataFormat has been changed to give the
File Group Descritor formats priority over the Internet Shortcut format.
This resolves a problem where dropping an URL on the desktop would cause the
desktop to assume that an Active Desktop item was to be created instead of
an Internet Shortcut.
Thanks to Allen Martin for reporting this problem.
By luck this modification also happens to work around a bug in Mozilla and
Netscape 6; Mozilla incorrectly supplies the UniformResourceLocator
clipboard format in unicode format instead of ANSI format.
Thanks to Florian Kusche for reporting this problem.
* Added support for TFileGroupDescritorWClipboardFormat to TURLDataFormat.
* Added declaration of FD_PROGRESSUI to DragDropFormats.
* Added TURLWClipboardFormat which implements the "UniformResourceLocatorW"
(a.k.a. CFSTR_INETURLW) clipboard format. Basically a Unicode version of
CFSTR_SHELLURL/CFSTR_INETURL.
The TURLWClipboardFormat class isn't used anywhere yet but will probably be
supported by TURLDataFormat (and thus TDropURLTarget/TDropURLSource) in a
later release.
* Added experimental Shell Drag Image support.
This relies on undodumented shell32.dll functions and probably won't be
fully support before v4.2 (if ever). See InitShellDragImage in
DropSource.pas.
Thanks to Jim Kueneman for bringning these functions to my attention.
13-oct-2001
* TCustomDropSource.Destroy and TCustomDropMultiSource.Destroy changed to call
FlushClipboard instead of EmptyClipboard.
This means that clipboard contents will be preserved when the source
application/component is terminated.
* Added clipboard support to VirtualFileStream demo.
* Modified VirtualFileStream demo to work around clipboard quirk with IStream
medium.
* Modified TCustomSimpleClipboardFormat to disable TYMED_ISTORAGE support by
default.
At present TYMED_ISTORAGE is only supported for drop targets and enabling it
by default in TCustomSimpleClipboardFormat.Create caused a lot of clipboard
operations (e.g. copy/paste of text) to fail.
Thanks to Michael J Marshall for bringing this problem to my attention.
* Modified TCustomSimpleClipboardFormat to read from the the TYMED_ISTREAM
medium in small (1Mb) chunks and via a global memory buffer.
This has resultet in a huge performance gain (several orders of magnitude)
when transferring large amounts of data via the TYMED_ISTREAM medium.
3-oct-2001
* Fixed bug in TCustomDropSource.SetImageIndex.
Thanks to Maxim Abramovich for spotting this.
* Added missing default property values to TCustomDropSource.
Thanks to Maxim Abramovich for spotting this.
* DragDrop.pas and DragDropContext.pas updated for Delphi 4.
* Reimplemented utility to convert DFM form files from Delphi 5/6 test format
to Delphi 4/5 binary format.
* Improved unregistration of Shell Extensions.
Shell extension now completely (and safely) remove their registry entries
when unregistered.
* Deprecated support for C++ Builder 3.
* Released for test as v4.1 FT2.
25-sep-2001
* Rewritten ContextMenuHandlerShellExt demo.
The demo is now actually a quite useful utility which can be used to
register and unregister ActiveX controls, COM servers and type libraries. It
includes the same functionality as Borland's TRegSvr utility.
20-sep-2001
* Added support for cascading menus, ownerdraw and menu bitmaps to
TDropContextMenu component.
* Modified TFileContentsStreamOnDemandClipboardFormat to handle invalid
parameter value (FormatEtcIn.lindex) when data is copied to clipboard.
This works around an apparent bug in the Windows clipboard. Thanks to Steve
Moss for reporting this problem.
* Modified TEnumFormatEtc class to not enumerate empty clipboard formats.
Thanks to Steve Moss for this improvement.
1-sep-2001
* Introduced TCustomDropTarget.AutoRegister property.
The AutoRegister property is used to control if drop target controls should
be automatically unregistered and reregistered when their window handle is
recreated by the VCL. If AutoRegister is True, which is the default, then
automatic reregistration will be performed.
This property was introduced because the hidden child control, which is used
to monitor the drop target control's window handle, can have unwanted side
effects on the drop target control (e.g. TToolBar).
* Deprecated support for Delphi 3.
22-jun-2001
* Redesigned TTextDataFormat to handle RTF, Unicode, CSV and OEM text without
conversion.
Moved TTextDataFormat class to DragDropText unit.
Added support for TLocaleClipboardFormat.
* Surfaced new text formats as properties in TDropTextSource and
TDropTextTarget.
Previous versions of the Text source and target components represented all
supported text formats via the Text property. In order to enable users to
handle the different text formats independantly, the text source and target
components now has individual properties for ANSI, OEM, Unicode and RTF text
formats.
The text target component can automatically synthesize some of the formats
from the others (e.g. OEM text from ANSI text), but applications which
previously relied on all formats being represented by the Text property will
have to be modified to handle the new properties.
* Added work around for problem where TToolBar as a drop target would display
the invisible target proxy window.
* Fixed wide string bug in WriteFilesToZeroList.
Thanks to Werner Lehmann for spotting this.
15-jun-2001
* Added work-around for Outlook Express IDataObject.QueryGetData quirk.
3-jun-2001
* Ported to C++ Builder 4 and 5.
* Added missing DragDropDesign.pas unit to design time packages.
* First attempt at C++ Builder 3 port.... failed.
* Improved handling of oversized File Group Descriptor data.
* Added support for IStorage medium to TFileContentsStreamClipboardFormat.
This allows the TDropComboTarget component to accept messages dropped from
Microsoft Outlook.
This work was sponsored by ThoughtShare Communications Inc.
23-may-2001
* Ported to Delphi 4.
* First attempt at C++ Builder 5 port.... failed.
18-may-2001
* Released as version 4.0.
Note: Version 4.0 was released exclusively on the Delphi 6 Companion CD.
* ContextMenuDemo and DropHandlerDemo application has been partially
rewritten and renamed.
ContextMenuDemo is now named ContextMenuHandlerShellExt.
DropHandlerDemo is now named DropHandlerShellExt.
* TDropContextMenu component has been rewitten.
The TDropContextMenu now implements a context menu handler shell extension.
In previous releases it implemented a drag drop handler shell extension.
* The DragDropHandler.pas unit which implements the TDropHandler component
has been renamed to DropHandler.pas.
* Added new TDragDropHandler component.
The new component, which lives in the DragDropHandler unit, is used to
implement drag drop handler shell extensions.
* Added DragDropHandlerShellExt demo application.
* Removed misc incomplete demos from kit.
* Fixed minor problem in VirtualFileStream demo which caused drops from
the VirtualFile demo not to transfer content correctly.
11-may-2001
* Converted all demo forms to text DFM format.
This has been nescessary to maintain compatibility between all supported
versions of Delphi.
* Fixed a bug in GetPIDLsFromFilenames which caused drag-link of files (dtLink
with TDropFileSource) not to work.
* Added readme.txt files to some demo applications.
* Added missing tlb and C++ Builder files to install kit.
* Released as FT4.
6-may-2001
* Added missing dfm files to install kit.
* Tested with Delphi 5.
Fixed Delphi 5 compatibility error in main.dfm of DragDropDemo.
* Removed misc compiler warnings.
* The AsyncTransferTarget and OleObjectDemo demos were incomplete and has been removed
from the kit for the V4.0 release.
The demos will be included in a future release.
* Released as FT3.
3-may-2001
* Added missing dpr and bpg files to install kit.
* Updated readme.txt with regard to lack of C++ Builder demos.
* Released as FT2.
29-apr-2001
* Cleaned up for release.
* Released as FT1.
23-feb-2001
* Modified TCustomDropTarget.FindTarget to handle overlapping targets (e.g.
different targets at the same position but on different pages of a page
control or notebook).
Thanks to Roger Moe for spotting this problem.
13-feb-2001
* Renamed AsyncTransfer2 demo to AsyncTransferSource.
* Added AsyncTransferTarget demo.
* Replaced TChart in AsyncTransfer2 demo with homegrown pie-chart-thing.
* Modified all IStream based target formats to support incremental transfer.
* URW533 problem has finally been fixed.
The cause of the problem, which is a bug in Delphi, was found by Stefan
Hoffmeister.
* Fixed free notification for TDropContextmenu and TDataFormatAdapter.
27-dec-2000
* Moved TVirtualFileStreamDataFormat and TFileContentsStreamOnDemandClipboardFormat
classes from VirtualFileStream demo to DragDropFormats unit.
* Added TClipboardFormat.DataFormat and TClipboardFormats.DataFormat property.
* Added TDropEmptySource and TDropEmptyTarget components.
These are basically do-nothing components for use with TDataFormatAdapter.
* Rewritten AsyncTransfer2 demo.
The demo now uses TDropEmptySource, TDataFormatAdapter and
TVirtualFileStreamDataFormat to transfer 10Mb of data with progress
feedback.
* Rewritten VirtualFileStream demo.
The demo now uses TDropEmptySource, TDropEmptyTarget, TDataFormatAdapter and
TVirtualFileStreamDataFormat.
* Fixed memory leak in TVirtualFileStreamDataFormat.
This leak only affected the old VirtualFileStream demo.
* Added support for full File Descriptor attribute set to
TVirtualFileStreamDataFormat.
It is now possible to specify file attributes such as file size and last
modified time in addition to the filename. I plan to add similar features to
the other classes which uses FileDescriptors (e.g. TDropFileSource and
TDropFileTarget).
21-dec-2000
* Ported to Delphi 4.
* Added workaround for design bug in either Explorer or the clipboard.
Explorer and the clipboard's requirements to the cursor position of an
IStream object are incompatible. Explorer requires the cursor to be at the
beginning of stream and the clipboard requires the cursor to be at the end
of stream.
15-dec-2000
* Fixed URW533 problem.
I'll leave the description of the workaround in here for now in case the
problem resurfaces.
11-dec-2000
* Fixed bug in filename to PIDL conversion (GetPIDLsFromFilenames) which
affected TDropFileTarget.
Thanks to Poul Halgaard J鴕gensen for reporting this.
4-dec-2000
* Added THTMLDataFormat.
* Fixed a a few small bugs which affected clipboard operations.
* Added {$ALIGN ON} to dragdrop.inc.
Apparently COM drag/drop requires some structures to be word alligned.
This change fixes problems where some of the demos would suddenly stop
working.
* The URW533 problem has resurfaced.
See the "Known problems" section below.
13-nov-2000
* TCopyPasteDataFormat has been renamed to TFeedbackDataFormat.
* Added support for the Windows 2000 "TargetCLSID" format with the
TTargetCLSIDClipboardFormat class and the TCustomDropSource.TargetCLSID
property.
* Added support for the "Logical Performed DropEffect" format with the
TLogicalPerformedDropEffectClipboardFormat class. The class is used
internally by TCustomDropSource.
30-oct-2000
* Added ContextMenu demo and TDropContextMenu component.
Demonstrates how to customize the context menu which is displayed when a
file is dragged with the right mouse button and dropped in the shell.
* Added TCustomDataFormat.GetData.
With the introduction of the GetData method, Data Format classes can now be
used stand-alone to extract data from an IDataObject.
20-oct-2000
* Added VirtualFileStream demo.
Demonstrates how to use the "File Contents" and "File Group Descritor"
clipboard formats to drag and drop virtual files (files which doesn't exist
physically) and transfer the data on-demand via a stream.
14-oct-2000
* Added special drop target registration of TCustomRichEdit controls.
TCustomRichEdit needs special attention because it implements its own drop
target handling which prevents it to work with these components.
TCustomDropTarget now disables a rich edit control's built in drag/drop
handling when the control is registered as a drop target.
* Added work around for Windows bug where IDropTarget.DragOver is called
regardless that the drop has been rejected in IDropTarget.DragEnter.
12-oct-2000
* Fixed bug that caused docking to interfere with drop targets.
Thanks to G. Bradley MacDonald for bringing the problem to my attention.
30-sep-2000
* The DataFormats property has been made public in the TCustomDropMultiTarget
class.
* Added VirtualFile demo.
Demonstrates how to use the TFileContentsClipboardFormat and
TFileGroupDescritorClipboardFormat formats to drag and drop a virtual file
(a file which doesn't exist physically).
28-sep-2000
* Improved drop source detection of optimized move.
When an optimized move is performed by a drop target, the drop source's
Execute method will now return drDropMove. Previously drCancel was returned.
The OnAfterDrop event must still be used to determine if a move operation
were optimized or not.
* Modified TCustomDropTarget.GetPreferredDropEffect to get data from the
current IDataObject instead of from the VCL global clipboard.
18-sep-2000
* Fixed bug in DropComboTarget caused by the 17-sep-2000 TStreams
modification.
17-sep-2000
* Added AsyncTransfer2 demo to demonstrate use of TDropSourceThread.
* Renamed TStreams class to TStreamList.
29-aug-2000
* Added TDropSourceThread.
TDropSourceThread is an alternative to Windows 2000 asynchronous data
transfers but also works on other platforms than Windows 2000.
TDropSourceThread is based on code contributed by E. J. Molendijk.
24-aug-2000
* Added support for Windows 2000 asynchronous data transfers.
Added IAsyncOperation implementation to TCustomDropSource.
Added TCustomDropSource.AllowAsyncTransfer and AsyncTransfer properties.
5-aug-2000
* Added work around for URW533 compiler bug.
* Fixed D4 and D5 packages and updated a few demos.
Obsolete DropMultiTarget were still referenced a few places.
* Documented work around for C++ Builder 5 compiler error.
See the Known Problems section later in this document for more information.
2-aug-2000
* The package files provided in the kit is now design-time only packages.
In previous versions, the packages could be used both at design- and
run-time. The change was nescessary because the package now contains
design-time code.
* Added possible work around for suspected C++ Builder bug.
The bug manifests itself as a "Overloadable operator expected" compile
time error. See the "Known problems" section of this document.
* Rewrote CustomFormat1 demo.
* Added CustomFormat2 demo.
* TDataDirection members has been renamed from ddGet and ddSet to ddRead and
ddWrite.
* All File Group Descritor and File Contents clipboard formats has been moved
from the DragDropFile unit to the DragDropFormats unit.
* File Contents support has been added to TTextDataFormat.
The support is currently only enabled for drop sources.
* Renamed TDropMultiTarget component to TDropComboTarget.
Note: This will break applications which uses the TDropMultiTarget
component. You can use the following technique to port application from
previous releases:
1) Install the new components.
2) Repeat step 3-8 for all units which uses the TDropMultiTarget component.
3) Make a backup of the unit (both pas and dfm file) just in case...
4) Open the unit in the IDE.
5) In the .pas file, replace all occurances of "TDropMultiTarget" with
"TDropComboTarget".
6) View the form as text.
7) Replace all occurances of "TDropMultiTarget" with "TDropComboTarget".
8) Save the unit.
* Renamed a lot of demo files and directories.
* Added work around for yet another bug in TStreamAdapter.
* Added TCustomStringClipboardFormat as new base class for
TCustomTextClipboardFormat.
This changes the class hierachy a bit for classes which previously
descended from TCustomTextClipboardFormat: All formats which needs zero
termination now descend from TCustomTextClipboardFormat and the rest descend
from TCustomStringClipboardFormat.
Added TrimZeroes property.
Fixed zero termination bug in TCustomTextClipboardFormat and generally
improved handling of zero terminated strings.
Disabled zero trim in TCustomStringClipboardFormat and enabled it in
TCustomTextClipboardFormat.
23-jul-2000
* Improved handling of long file names in DropHandler demo.
Added work around for ParamStr bug.
* Added TDataFormatAdapter component and adapter demo.
TDataFormatAdapter is used to extend the existing source and target
components with additional data format support without modifying them. It
can be considered an dynamic alternative to the current TDropMultiTarget
component.
17-jul-2000
* TDropHandler component and DropHandler demo fully functional.
14-jul-2000
* Tested with C++ Builder 5.
* Fixed sporadic integer overflow bug in DragDetectPlus function.
* Added shell drop handler support with TDropHandler component.
This is a work in progress and is not yet functional.
1-jul-2000
* Tested with Delphi 4.
* Support for Windows 2000 inter application drag images.
* TRawClipboardFormat and TRawDataFormat classes for support of arbitrary
unknown clipboard formats.
The classes are used internally in the TCustomDropSource.SetData method to
support W2K drag images.
本文探讨了C/C++混合编程中因内存分配与释放接口不匹配导致的问题，并提供了解决方案。强调使用正确的内存管理函数对配对至关重要。
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