Property expression IFNA (or similar)

[Bruce]

There needs to be an expression that tests for a non-existent property.  Excel's formulas IFNA, or IFERROR are along the lines of what I'm thinking.

An example would be when you have several properties that are for independent information (wall type, fire rating, acoustic rating, etc), that then concatenate in yet another property for a completed code.  If one of the properties is missing because it isn't included in the element's classification, the result is #propertyName.  There needs to be a way to error handle this.

E.g. CONCAT(IFNA(Property 1, ""), " | ", IFNA(Property 2, ""))

[Lee Hankins]

I’ve kind of done a workaround to this. Where we have created our own properties which are based on an option set I have set one of the options to be ‘Select’ which should never be the option used. I then have an expression that says if that property is defined as ‘Select’ then display ‘ERROR’ in the label. 

[Bruce]

Thanks Lee, but not quite the same thing.  If Property 1 doesn't exist in the element's classification, then it won't report anything to the enquiring Property.  

[Bruce · Accepted solution]

Wish submitted.

https://community.graphisoft.com/t5/Wishes-forum/Property-expression-IFNA-or-similar/td-p/370335