TDragDropFiles is a component for simple OLE drag-and-drop operations with files. The component is a child-class from TDragDrop.

I publish this component simultaneously with TDragDropFilesEx to avoid a brutal code breaking that could discourage some programmers. Probably, I won't enhance the component any longer.

Shortcuts does only support the component TDragDropFilesEx!

This is a help file for the archive DragNDrop.zip and DragNDrop(D2).zip. It maybe, that the description in this file doesn't work with both versions, but I've tried to care about all differences.

The author disclaims all warranties, expressed or implied, including, without limitation, the warranties of merchantability and of fitness for any purpose. The author assumes no liability for damages, direct or consequential, which may result from the use of this component/unit.

This component is copyright 1998 by Dieter Steinwedel. ALL RIGHTS ARE RESERVED BY DIETER STEINWEDEL. You are allowed to use it freely subject to the following restrictions:
• You are not allowed delete or alter the author's name and copyright in any manner

• You are not allowed to publish a copy, modified version or compilation neither for payment in any kind nor freely

• You are allowed to create a link to the download in the WWW

• These restrictions and terms apply to you as long as until I alter them. Changes can found on my homepage

Version 1.00 published on ??-Nov-1997
• First official release

Version 1.01 published on 3-Feb-1998
• Some properties were added
• New demo
• New handling on dwEffect

Version 1.02 published on 10-Jun-1998
• The result of the ExecuteDragDrop-method has changed (new result type)

Version 1.03 published on 29-Jun-1998
• A bug was removed (accepting files)

Version 2.00 published on 06-Aug-1998
• Internal structure was totally re-designed (has now the mother-class TDragDrop), but the handling hasn't changed

Version 3.00 published on 03-Oct-1998
• Total internal redesign due to modifications of the mother-class, but the handling hasn't changed
• component's icon has changed

Version 3.01 published on 07-Oct-1998
• small invisible bugs fixed

This is a component created by Dieter Steinwedel.

• Windows9x or Windows NT 4+ (tested with Windows95)

• Delphi 2+ (tested with Delphi 2)

Install as common you install components. The component will appear in the group "system". Modify it, if you want.

The component is designed for easy use. For more infomation consult the Delphi online-help. In the most cases (okay, delete the "on" at "onXXXXXX" etc) you will get a help.
Here are only listed the new properties of the component. You find detailed infomation about the inherited properties etc. in the description of TDragDrop.

inherited properties

Click here

FileList public

For Target: Use this stringlist in OnProcessDropped, if you want to get the dropped files. For Source: Add the files to the stringlist, which you want to d&d, before calling Execute.

inherited events

Click here

inherited methods

Click here

Execute public

Call this method, if you detect that the user wants to start a d&d-operation (i.e.: MouseDown+MouseMove). -> FileList For drag detection you can also use the inherited property AutoDetectDnD or the method StartDnDDetection. If you are using a grid, check the section "Known Bugs" in the docu of the TDragDrop component.

1. Drop a TWinControl on the form (i.e.: Listbox)
2. Choose the TWinControl in DragDropControl (-> Listbox)
3. Choose the d&d effects under SourceEffects which the DragDropControl (-> Listbox) should support. (If you don't want that the DragDropControl serve as d&d source all items must be false.)
4. Now, your DragDropControl (-> Listbox) must detect, if the user wants to start a d&d-operation. You may use the event "OnMouseDown" of your DragDropControl (-> Listbox). Are items selected then add them to the FileList:


DragDropFiles1.FileList.add( <selected items of DragDropControl(-> Listbox)>);


You must add the filenames including the WHOLE PATH!!!
5. Tell windows9x there is a d&d-operation: Just call the method Execute of this component. Now windows handles the d&d-operation.
6. You may use the events OnGiveFeedback and OnQueryContinueDrag, but often you need not. For more info, see above.
7. Make a handstand!

Hint: d&d-operations cannot be done at design-time!
If you are using a grid, check the section "Known Bugs" in the docu of the TDragDrop component.

1. Drop a TWinControl on the form (i.e.: Listbox)
2. Choose a TWinControl in DragDropControl (-> Listbox)
3. Choose the d&d effects under TargetEffects which the DragDropControl (-> Listbox) should support. (If you don't want that the DragDropControl serve as d&d target, all items must be false.)
4. Now, you have to program what happen, if the user drops files on your DragDropControl (-> Listbox). For this use the event OnProcessDropped. At first you should check what d&d effect was chosen by the user. You get the effect from method parameter dwEffect. You get the files from this component:


... :=DragDropFiles1.FileList[<Index>];


FileList is a stringlist. For more info check the Delphi's online-help. Now, do with the files what you have to do, i.e. copy, move, delete, etc.
5. You may use the events OnDragEnter, OnDragOver and OnDragLeave, but often you need not. For more info, see above.
6. Make a handstand and clap with your hands! ;)

Hint: d&d-operations cannot be done at design-time!

Please mail me only bugs and fixes. Don't ask for help, I DON'T ANSWER (no time)!!!! But before you contact me, check my homepage. I will publish bugs and fixes etc. Write a SHORT email in english or german.

Of course, I'm interested in YOUR improvements. I always try to increase the quality of my components! Therefore, mail me your improvements, please. Thanks!


email: dsteinwe@rz.uni-osnabrueck.de
homepage: http://godard.oec.uni-osnabrueck.de/student_home/dsteinwe/delphi/DietersDelphiSite.htm

• Shortcuts to desktop or explorer, etc. aren't possible. You must use the component TDragDropFilesEx to have this feature

© 1998 by Dieter Steinwedel

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