TPJDropFiles Component

Contents

• Description
• Compatibility
• Installation
• Known Issues
• Update History
• License and Disclaimer
• About the Author

Description

This component provides a window which can accept files dragged and dropped from File Manager (Win 3.1) or Explorer (Win 95/8). The window takes on the appearance of its parent window, although anything drawn on the parent's canvas is obliterated.

The control can contain child components (in a similar way to TPanel components). Files dropped over any such child component are accepted by the parent TPJDropFiles component. The TPJDropFiles component can be aligned with the form on which it is placed using the Align property.

When files from File Manager or Explorer are dropped over this component the OnDropFiles event is triggered. The names of the files are recorded in the Files property and the number of files dropped is held in the Count property.

The point at which the files were dropped is given by the DropPoint property (in coordinates relative to the control). The DropControl property idenitfies any child control that was under the mouse cursor when the files were dropped.

The component accepts dropped files only if the Enabled property is True.

Compatibility

This component has been tested with Delphi 1, 2, 3 and 4. It may work correctly in Delphi 5 but this has not been tested.

Installation

In these instructions $(DELPHI) is to be taken to represent the path where the appropriate version of Delphi was installed. For example, if you have Delphi 2 installed on the default installation path then $(DELPHI) is equivalent to C:\Program Files\Borland\Delphi 2.0.

Installation with Delphi 1

1. Unzip the file drpfiles.zip into a folder, preserving the directory structure.
2. Copy the file drpfiles.pas to the folder from where you wish to install the component into the Delphi Component Palette. This will probably be an existing folder where you keep the library components - say the default $(DELPHI)\lib folder.
3. Copy drpfiles.dcr from the 16 sub-folder into the same place that you copied drpfiles.pas.
4. Copy the help file drpfiles.hlp into the $(DELPHI)\bin folder.
5. Copy the help keyword file drpfiles.kwf into the $(DELPHI)\help folder.
6. Ensure Delphi is not running. Merge the help keyword file by running helpinst.exe from the $(DELPHI)\help folder. When helpinst.exe is running open the delphi.hdx file and add drpfiles.kwf and click on the Save button.
7. Start Delphi. Select the Options | Install Components menu option. Click the Add button, then the Browse button and navigate to the drpfiles.pas file in the directory where you placed it. Click OK to recompile the components library.
8. You can now delete drpfiles.pas from the place where you copied it if you wish. The component will appear on a palette called PJ Stuff. You can move the component to a different palette as required, or hack the source code (before installing the component) by finding the Register procedure at the end of the code and changing the string 'PJ stuff' to the name of the required palette.

Installation with Delphi 2

1. Unzip the file drpfiles.zip into a folder, preserving the directory structure.
2. Copy the file drpfiles.pas to the folder from where you wish to install it into the Delphi Component Palette. This will probably be an existing folder where you keep the library components - say the default $(DELPHI)\lib folder.
3. Copy drpfiles.dcr from the 32 sub-folder into the same place that you copied drpfiles.pas.
4. Copy the help file drpfiles.hlp into the $(DELPHI)\help folder.
5. Copy the help keyword file drpfiles.kwf into the $(DELPHI)\help folder.
6. Merge the help keyword file by running helpinst.exe from the $(DELPHI)\help\tools folder. When helpinst.exe is running open the delphi.hdx file and add drpfiles.kwf and click on the Save button.
7. Start Delphi. Select the Options | Install Components menu option. Click the Add button, then the Browse button and navigate to the drpfiles.pas file in the folder where you placed it. Click OK to recompile the components library.
8. You can now delete drpfiles.pas from the place where you copied it if you wish. The component will appear on a palette called PJ Stuff. You can move the component to a different palette as required, or hack the source code (before installing the component) by finding the Register procedure at the end of the code and changing the string 'PJ stuff' to the name of the required palette.

Installation with Delphi 3 & Delphi 4

Note that although the provided help file gives information about using the component it cannot be linked into the Delphi 3 or Delphi 4 environments at present.

1. Unzip the file drpfiles.zip into a folder, preserving the directory structure.
2. Copy the file drpfiles.pas to the folder from where you wish to install the component into the Delphi Component Palette. This will probably be a sub-folder of the $(DELPHI)\lib folder.
3. Copy drpfiles.dcr from the 32 sub-folder into the same place that you copied drpfiles.pas.
4. Install the component into the palette by chosing the Component | Install Component menu option. The following instructions assume you are installing into the default "users components" package:
   • Select the "Into exisiting package" page of the Install Components dialogue box.
   • Browse to the folder where you saved drpfiles.pas and select the file.
   • Ensure that the "Package file name" edit box contains $(DELPHI)\lib\dclusrXX.dpk (where XX=30 for Delphi 3 and XX=40 for Delphi 4).
   • Accept that the package will be rebuilt.
   • A dialogue box should be displayed saying that TPJDropFiles has been added to the component palette.
5. You can now delete drpfiles.pas from the place where you copied it if you wish. The component will appear on a palette called PJ Stuff. You can move the component to a different palette as required, or hack the source code (before installing the program) by finding the Register procedure at the end of the code and changing the string 'PJ stuff' to the name of the required palette.

Known Issues

• Using Delphi 2 (or Delphi 1 under Win 95/8) it is possible that the first time you try to access the help file by selecting the component on a form and pressing F1 (or from a property in the object inspector) the help file may not be found. In this case find the help file manually (in the $(DELPHI)\bin folder for Delphi 1 or the $(DELPHI)/help folder for Delphi 2). The location of the help file will be remembered in future.
• It is not at present possible to integrate the help file into the IDE with Delphi 3 and Delphi 4.

Update History

Un-released
DrpFiles v1.0 of 15/05/1998

• Original version - 16 bit only.

Un-released
DrpFiles v1.1 of 22/10/1998

• Changed 2nd parameter to DragQueryFile when used to find number of files dropped from $FFFF to Cardinal(-1) to make it portable across 16 and 32 bit platforms. This was needed to allow the component to compile under Delphi 2.

Release 1.1 of 10/07/1999
DrpFiles v1.1a of 09/04/1999

• Changed installation palette from "Own" to "PJ Stuff".
• Added HTML documentation.

Release 1.1.1 of 28/11/1999
DrpFiles v1.1a of 09/04/1999

• Updated HTML documentation to include installation notes for Delphi 3/4 and added update history.

License & Disclaimer

This component is copyright © P.D.Johnson, 1998-1999.

The source code and help files can be freely distributed on a not-for-profit basis providing that:

1. the source code is not altered.
2. this readme file is distributed with it unchanged

By not-for-profit I mean that you may recover out of pocket expenses incurred in distributing the code, but should not make a profit from this.

If you discover any bugs in this implementation, or if you have any update suggestions, please contact me on peter.johnson@openlink.org.

Please do modify the code for you own use. I'd like to see any changes you make - I could incorporate them into future versions. Please notify me of changes on at the above e-mail address.

This software is provided as is - no warranty is given as to its suitability for any purposes to which you may wish to put it.

About the Author

I'm Peter Johnson - a hobbyist programmer living in Ceredigion in West Wales, UK. I write mainly in Delphi, but occasionally dabble in C, C++ and Java. My programs are available for download on my web-site: http://homepages.tesco.net/~p.d.johnson/.

I can be contacted by e-mail on peter.johnson@openlink.org.