TPJWdwState & TPJRegWdwState Components

Contents

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

Description

The file wdwstate.pas includes two components - TPJWdwState and TPJRegWdwState, along with a property editor (TPJHKEYPropEditor) for editing the registry root key property of TPJRegWindowState.

The components can save the state (minimised, maximised or normal) of a form window, along with its size and position. TPJWdwState saves the information to a ini file while TPJRegWdwState saves to the registry. The components can also read information back and restore the saved window settings. This means the components can be used to restore a window to the condition it was in during some previous execution, just by calling a couple of methods.

With TPJWdwState you can specify the name of the ini file, or let the component choose one. You can also decide the name of the section within the ini file that will be used. Again the component can provide a suitable default section name.

Similarly with TPJRegWdwState you can specify the registry root and sub-keys under which the information is saved. Again suitable default values are used if no keys are specified.

Also included in the wdwstate.pas unit is the component TPJCustomWdwState. This component is an abstract base class for both TPJWdwState and TPJRegWdwState.

Compatibility

The components and property editor have been tested with Delphi 2, 3 and 4. It is likely that they will work with Delphi 5, but this has not been tested. They are not compatible with Delphi 1.

An older version of TPJWdwState that is compatible with Delphi 1 is available from my website.

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 2

1. Unzip the file wdwstate.zip into a folder, preserving the directory structure.
2. Copy wdwstate.pas, wdwstate.dcr and PJHKEYPropEdit.pas to the folder from where you wish to install the components into the Delphi Component Palette. This will probably be an existing folder where you keep library components - say the default $(DELPHI)\lib sub-folder.
3. Copy the help files wdwstate.hlp and wdwstatr.hlp and the keyword files wdwstate.kwf and wdwstatr.kwf into the $(DELPHI)\help folder.
4. Merge the help keyword files by running helpinst.exe from the $(DELPHI)\help\tools folder. When helpinst.exe is running open the delphi.hdx file and add wdwstate.kwf and wdwstatr.kwf and click on the Save button.
5. Start Delphi. Select the Component | Install menu option. Click the Add button, then the Browse button and navigate to the wdwstate.pas file in the folder where you placed it. If you wish to also add the property editor then repeat the process with PJHKEYPropEdit.pas. Click OK to recompile the component library.
6. You can now delete wdwstate.pas and PJHKEYPropEdit.pas from the place where you copied them if you wish. The components will appear on a palette called PJ Stuff. You can move the components to a different palette as required, or hack the source code (before installing the components) by finding the Register procedure at the end of wdwstate.pas 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 files give information about using the components they cannot be linked into the Delphi 3 or Delphi 4 environments at present.

1. Unzip the file wdwstate.zip into a folder, preserving the directory structure.
2. Copy wdwstate.pas, wdwstate.dcr and PJHKEYPropEdit.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. Install the components and property editor 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 wdwstate.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).
   • Repeat the above process with PJHKEYPropEdit.pas if you also wish to install the property editor.
   • Accept that the package will be rebuilt.
   • A dialogue box should be displayed saying that TPJWdwState and TPJRegWdwState have been added to the component palette.
4. You can now delete wdwstate.pas and PJHKEYPropEdit.pas from the place where you copied them if you wish. The components will appear on a palette called PJ Stuff. You can move the components to a different palette as required, or hack the source code (before installing the components) by finding the Register procedure at the end of wdwstate.pas and changing the string 'PJ stuff' to the name of the required palette.

Known Issues

• When restoring a form's state, and the form was minimised when the state was saved, the form's normal window may briefly flash on screen before being minimized. This occurs if the form's constraints (Delphi 4 and later) are non-zero.
• Using Delphi 2 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 $(DELPHI)/help folder for Delphi 2). The location of the help file will be remembered in future.
• There is no context sensitive help registered under Delphi 2 for TPJRegWdwState's AutoSaveRestore property -- the Delphi keyword generator couldn't handle the legnth of the required keyword.
• It is not at present possible to integrate the help file into the IDE with Delphi 3 and Delphi 4.

Fixed

• Forms that were being displayed in a minimised state used to flash on screen. This was fixed in version 2.2.
• A maximised window was not restoring correctly (bug introduced in v3.0). Fixed in v3.1.
• Under certain circunstances and form would not load its other components correctly (bug introduced in v3.0). Fixed in v3.1.

Update History

Release 1.0 of 15/08/1999
WdwState v1.0 of 15/08/1999

• Original version - included just TPJWdwState component with HTML documentation.

Release 2.0 of 19/10/1999
WdwState v2.0 of 18/10/1999

• Re-write which added TPJRegWdwState component that stores window state information in registry.
• Extracted common functionality of TPJWdwState and TPJRegWdwState into new abstract base class TPJCustomWdwState.
• TPJWdwState presented same interface and functionality as version 1.
• TRegWdwState was not available when compiled under Delphi 1 (because it uses registry).
• Updated HTML documentation to deal with new classes.

Release 2.1 of 29/11/1999
WdwState v2.1 of 29/11/1999

• Renamed ReadState and SaveState methods to ReadWdwState and SaveWdwState respectively since ReadState was masking a method inherited from TComponent.
• Updated HTML documentation to include installation notes for Delphi 3/4 and added update history.

Release 3.0 of 05/04/2000
WdwState v3.0 of 05/04/2000

• Added AutoSaveRestore property to enable forms to be automatically saved and restored (thanks to Stefan Winter for suggesting this and providing prototype code).
• Modified window restoration code to avoid task bars in positions other than bottom of screen (again thanks to Stefan for pointing out the problem and providing prototype code to fix it)
• Prevented forms being restored as minimized from flashing on screen (by cheating!)
• Removed conditional compilation statements since this version will not compile under Delphi 1.

Release 3.1 of 29/04/2000
WdwState v3.1 of 29/04/2000

• Fixed a bug where windows that were supposed to be restored maximised to be displayed using the last saved window dimensions. This bug was also causing the form to fail to load other components under certain circumstances. (thanks to Andre Viol for reporting these bugs).

Release 3.1.1 of 08/10/2000
WdwState v3.1 of 29/04/2000
PJHKeyPropEdit v1.0.1 of 08/10/2000

• Added property editor for TPJRegWdwState's RegRootKey property.

Credits

Thanks are due to Stefan Winter for providing some of the code of version 2.2 and for adding a prototype version of the AutoSaveRestore property.

License & Disclaimer

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

1. the source code is not altered.
2. this 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://www.pjsoft.contactbox.co.uk/.

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