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RegisterPropertyEditor bug??

JimBob091197
JimBob091197 asked
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Last Modified: 2012-06-27
Delphi's RegisterPropertyEditor procedure has the following declaration:

procedure RegisterPropertyEditor(PropertyType: PTypeInfo; ComponentClass: TClass; const PropertyName: string; EditorClass: TPropertyEditorClass);

The help file says the following: "Set the PropertyName parameter to restrict the property editor to properties with a specific name as well as the specified property type."

I would like to override the TStrings property editor, but ONLY for properties with a "specific name" (as the help file says) e.g. Address.  Thus for ANY component with a TStrings-derived property called "Address" it must use my property editor, but for all other TStrings-derived properties (e.g. TMemo's "Lines" property) Delphi must use the original property editor.

The problem I'm having is that Delphi uses my editor for all TStrings properties (e.g. TMemo's "Lines" property), instead of only for properties called "Address".

This is what my original code looked like:

RegisterPropertyEditor(TypeInfo(TStrings), nil, 'Address', TAddressPropEd);

The way I got around this problem is to declare my own class that is derived from TStrings:
type
  TAddressStrings = class(TStringList);

RegisterPropertyEditor(TypeInfo(TAddressStrings), nil, 'Address', TAddressPropEd);

The above code works, but I don't understand why it's necessary to derive my own class (if the help file is correct).
(I've tried this in D3 and D4, and both give the same result.)

Thanks,
JB
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Commented:
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Author

Commented:
Thanks Zif.

Your comment "Third parameter: is valid ONLY if the second parameter is NOT nil" is what I was looking for.

The help file only says that you can set 3rd parameter (PropertyName) to "the property editor to properties with a specific name as well as the specified property type."

Note that "property type" is the 1st parameter, and the help file says nothing about what happens to the 3rd parameter (PropertyName) if the 2nd parameter (ComponentClass) is nil.

I figured this must be the case, else a bug, but thanks for clearing it up for me.

Cheers,
Dave

Author

Commented:
Sorry, 2nd paragraph above should read:

The help file only says that you can set 3rd parameter (PropertyName) to "RESTRICT the property editor to properties with a specific name as well as the specified property type."

-Dave

Commented:
Glad I could be of assitance. JB, seeing your q'ns : you must almost have finished a great new component package?

Author

Commented:
Not component package, but app!  ;-)  I will keep you informed...  I want to have a web site finished for it by end of November.

-Dave

Commented:
Hey Great! Let me know of it, surely!

Author

Commented:
Will do!

(For a sneak-preview go to http://www.geocities.com/SiliconValley/Lakes/9940/)

-Dave

Commented:
JB, woow. Nice! Now I understand why you were so silently!

Author

Commented:
Glad you liked it.  I'll be sure to keep you up-to-date.
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