Title: Design-Time Component About Box Dialog
Question: When I write a component I like to add an "About" property that displays an info dialog box diplaying the component version number and a brief description. In Delphi 5 I achieved this by using a Property Editor and Registering it within the component. Converting to Delphi 6 gave me a problem. Firstly the unit "dsgnintf" is no longer part of Delphi and secondly the supplied replacments "DesignIntf" and "DesignEditors" compile to a non-distributable EXE file. ("proxies.dcu" is part of the design-time non-distributable package).
What now ?
Surfing the web came up with solutions of creating BOTH run-time and design-time units. Whilst this is fine for a serious or complicated property editor, I did not wish to go these lengths for a simple about property.
The solution I have now adopted does the trick for me and is implemented as follows ..
Declare a property of boolean.
Display the info dialog box when set to true. (set to false after display)
This allows double clicking the false/true value (or selecting true) at design time, and if needed can be set at run-time by
MyComponent.About := true;
Answer:
Stripped down skeleton example ....
interface
uses Dialogs;
type
TLogFile = class(TComponent)
private
{ Private declarations }
...
FAbout : boolean;
...
...
procedure SetAbout(Value : boolean);
...
protected
{ Protected declarations }
...
public
{ Public declarations }
...
published
{ Published declarations }
...
property About : boolean read FAbout write SetAbout;
...
end;
implementation
procedure TLogFile.SetAbout(Value : boolean);
const CrLf = #13#10;
var msg : string;
begin
if Value then begin
// Display your dialog message here
msg := 'TLogFile v1.2' + CrLf + CrLf +
'ASCII Log File Component.' + CrLf +
'Logs to EXEPATH/.log' + CrLf +
'Automatically Truncates and moves to Archive' + CrLf +
'Log File (Extention .olg) after MaxLogSize.' + CrLf +
'(32 bit version - DELPHI VI)' + CrLf + CrLf +
'Copyright 2002 Mike Heydon';
MessageDlg(msg, mtInformation, [mbOK], 0);
end;
FAbout := false;
end;