topic Re: ACAPI_Element_Change in Archicad C++ API

ACAPI_Element_Change

Anonymous — Tue, 04 Oct 2022 14:31:45 GMT

I started with the Do_Word_Edit function found in ..\Examples\Element_Test in the Element_Modify.cpp file. I am using the true part of (mode==1) of the if to "Click a word to change its content". My intent is to change selected text to upper case. All existing code is untouched until after
"strcpy(*memo.textContent, text);"

Then:


		strcpy(*memo.textContent, text);

<my modification>
		// Test getting the memo of the existing text
		ACAPI_Element_GetMemo(element.header.guid, &memo, APIMemoMask_TextContent);
		CHtoUpper(*memo.textContent);
		JHP_Msg(*memo.textContent);  // displays selected text with conversion to upper case
</my modification>

		err = ACAPI_Element_Change(&element, &mask, &memo, APIMemoMask_TextContent, true);

<my modification>
		if (err != NoError) // always true.
		{
			JHP_Msg("There is an error.");
			JHP_Msg((strerror(err))); // Error message in plain English is "Unknown error"
		}
</my modification>

		ACAPI_DisposeElemMemoHdls(&memo);

I am having trouble with ACAPI_Element_Change. Since I believe my modifications are only the conversion to upper case and verification of error after ACAPI_Element_Change, I am not quite sure what I did to break it. In my mind, the ACAPI_Element_Change is operating just the same as it was used in the example from the Element_modify.cpp file.

What am I missing?

Thanks -
chris

Re: ACAPI_Element_Change

Anonymous — Wed, 29 May 2019 14:52:32 GMT

So it seems that adding this:


 return ACAPI_CallUndoableCommand("JHP Menu Command Function",
	[&]() -> GSErrCode {

to wrap my menu load that does the function call solves the problem.

And after I successfully convert my selected text to upper case, I can ^Z back to lower case. Not what I would expect with 'ACAPI_CallUndoableCommand'.

Can someone please explain???

thanks - chris

Re: ACAPI_Element_Change

Ralph Wessel — Wed, 29 May 2019 22:04:51 GMT

Functions like ACAPI_Element_Change cause changes to the database which the user should be able to undo. In order for these functions to work, you need to enclose them in ACAPI_CallUndoableCommand to prepare ARCHICAD for undoable changes. If you don't, ARCHICAD will refuse to complete the function and return an error.

Re: ACAPI_Element_Change

Anonymous — Thu, 30 May 2019 14:48:33 GMT

Thanks for the insight Ralph. It just sounds a little counter-intuitive. I feel like getting this first function call from my menu sets up a good template for the others that will follow. Thanks again for your help.
- chris

Re: ACAPI_Element_Change

Ralph Wessel — Fri, 31 May 2019 14:21:45 GMT

chrisgilmer wrote:
Thanks for the insight Ralph. It just sounds a little counter-intuitive

It might help if you think about it as a database transaction. Marking the beginning and end of a transaction allows that specific action to be rolled back, in this case by the user requesting an 'Undo'

Re: ACAPI_Element_Change

Anonymous — Fri, 31 May 2019 16:42:40 GMT

I get the database marks and thanks for emphasizing that part of it.

I just realized I was putting emphasis on the wrong syllables. I was reading it as "I am calling a command that does not respond to ^Z" instead of "I am calling a command that allows ^Z, therefore it is undoable".

"Let's eat grandma" vs. "Let's eat, grandma".

Thanks again -
chris