Expression Based Properties in AC 27 API

[Apollos]

Hello.

Please I need your assistance, I have been trying to write an expression for my Properties through the Archicad 27 C++ API, to sum two variables from the zone element. but I am yet to get the correct syntax. Please, any meaningful advice will be appreciated. Find below the code block snippet. Thank you.

//// Create expression property definitions for Area With Niches
API_PropertyDefinition expressionAreaWithNiches;
expressionAreaWithNiches.guid = APINULLGuid;
expressionAreaWithNiches.groupGuid = group.guid;
expressionAreaWithNiches.name = "Expression Area With Niches";
expressionAreaWithNiches.description = "This is the Room Area with recesses or niches";
expressionAreaWithNiches.collectionType = API_PropertySingleCollectionType;
expressionAreaWithNiches.valueType = API_PropertyRealValueType;
expressionAreaWithNiches.measureType = API_PropertyAreaMeasureType;
expressionAreaWithNiches.definitionType = API_PropertyCustomDefinitionType;
expressionAreaWithNiches.defaultValue.hasExpression = true;
expressionAreaWithNiches.defaultValue.propertyExpressions = {"SUM"{ "Measured Area", "Wall Inset Top Surface"} };

err = ACAPI_Property_CreatePropertyDefinition(expressionAreaWithNiches);

[Akos Somorjai]

Hi,

Could you please try:

expressionAreaWithNiches.defaultValue.propertyExpressions = {"SUM ( {Property:2FEF2535-7688-4A26-A0C8-2E892CBDCFD8}, {Property:D53B1F63-5552-47FB-BD5B-FB1F57FEACEA} )"};

Akos

[Apollos]

Hello @Akos Somorjai , thank you for your response. I just tried it but it compiled without errors but it did not execute its task. Please, is this the expression property string GUIDS or what? Please. I await your feedback.

[Akos Somorjai]

Hi,

Yes, they are. You can try to get the GUIDs if you create the same property in the Property Manager, then export it as an XML file.

[Apollos]

OK. I will do that NOW... I will get back to you.

[Apollos]

Hello @Akos Somorjai , I just tried it but it does not work. Or am I missing something? I really want to understand the expression syntax.

[Apollos]

Hello? Is there any update or alternative please?

[Bernd - Archi-XT · Accepted solution]

I played around and was able to figure out a working example. This code works for me (AC27):

API_PropertyDefinition expressionAreaWithNiches{};
expressionAreaWithNiches.guid = APINULLGuid;
expressionAreaWithNiches.groupGuid = group.guid;
expressionAreaWithNiches.name = "Expression Area With Niches";
expressionAreaWithNiches.description = "This is the Room Area with recesses or niches";
expressionAreaWithNiches.collectionType = API_PropertySingleCollectionType;
expressionAreaWithNiches.valueType = API_PropertyRealValueType;
expressionAreaWithNiches.measureType = API_PropertyAreaMeasureType;
expressionAreaWithNiches.definitionType = API_PropertyCustomDefinitionType;
expressionAreaWithNiches.canValueBeEditable = true;
expressionAreaWithNiches.defaultValue.basicValue.singleVariant.variant.type = expressionAreaWithNiches.valueType;
expressionAreaWithNiches.defaultValue.hasExpression = true;
expressionAreaWithNiches.defaultValue.propertyExpressions = {
  "SUM ( ###Property:2FEF2535-7688-4A26-A0C8-2E892CBDCFD8###, ###Property:D53B1F63-5552-47FB-BD5B-FB1F57FEACEA### )"
};
err = ACAPI_Property_CreatePropertyDefinition (expressionAreaWithNiches);

Weirdly enough, the expression syntax I used in that code is reported as an incorrect expression syntax by ACAPI_Property_CheckPropertyExpressionString (available since AC27).

The following two syntax variations are accepted by ACAPI_Property_CheckPropertyExpressionString, but they don't work with ACAPI_Property_CreatePropertyDefinition!

"SUM ({Property:Zone / Measured Area}, {Property:Zone / Wall Inset Top Surface Area}) "
"SUM ( {Property:2FEF2535-7688-4A26-A0C8-2E892CBDCFD8}, {Property:D53B1F63-5552-47FB-BD5B-FB1F57FEACEA} )"

 Seems like strange behavior. Is this intended @Akos Somorjai?

Best,
Bernd

[Akos Somorjai · Accepted solution]

Hi @Bernd - Archi-XT ,

Thanks for checking!

Using '{}' as separators doesn't work, but '###' does:

"SUM (###Property:Zone / Measured Area###, ###Property:Zone / Wall Inset Top Surface Area###)"

Best, Akos

[Apollos]

Dear @Bernd - Archi-XT , that was my last thought. After I tried the suggestion of @Akos Somorjai ....I realised that every time I call the ACAPI_Property_GetPropertyExprReferenceString() function it gives me the ###......###.

Now you sent it...THANK YOU @Bernd - Archi-XT  & @Akos Somorjai  for your help. I am learning alot.