SearchForPropertyEx doesn't actually return a NULL?

Question

Dim propEffDate
Dim effDatePropDef

effDatePropDef = Vault.PropertyDefOperations.GetPropertyDefIDByAlias("M-Files.Property.EffectiveDate")

'Does the Object already have the Effective Date Property?
set propEffDate = PropertyValues.SearchForPropertyEx(effDatePropDef, true)

IF IsNULL(propEffDate) THEN
 Err.Raise 2, "NULL"
END IF
IF IsEmpty(propEffDate) THEN
 Err.Raise 3, "Empty"
END IF
IF IsObject(proEffDate) THEN
 IF proEffDate IS NOTHING THEN
 Err.Raise 5, "Nothing"
 END IF
 Err.Raise 4, "Object"
END IF 
 I am running this script in a State Action where I want to set the value of a Property. The Property may or may not be attached to the object so I am searching for the PropertyDef by Alias, then using this value to search the PropertyValues collection to see if the Property is included. However this Code triggers NONE of the Err.Raise (which I am just using to diagnose the behavior). I was expecting the IsNULL check to be true since that is what the documentation implies is the purpose of the SearchForPropertyEx call. But whatever is returned is neither NULL nor an Object so the code happily bypasses all these IF statements. What should I be expecting here. 
 Also, is there any way to perform logging from within a script? It is extremely difficult to observe what is happening. 
 -Jason

ant_ibrahim · Accepted Answer

If all you want to do is validate if the property is on the PropertyValues, you can also do the following 
 ' if the property is not on the metadata card , it returns a -1 for the index. 
IF PropertyValues.IndexOf(propEffDate) > -1 Then
 ' put code here
END IF 
 As for additional logging, the main way to troubleshoot is to use the Err.Raise like you are doing. On rare occasions for bigger scripts I also sometimes add an "on error resume next" on the top of my script to let it run through all the if statements and have it append my messages to a variable which I then output to a multi text value property so I can see everything at once.

Craig Hawker · Answer

Hi Jason, 
 If you're looking for a more comprehensive development experience then you probably want to look at the Vault Application Framework: The Vault Application Framework (m-files.com) . There is also the Vault Application Logging Framework: Logging (m-files.com) . The two can work together. This will give you a proper development environment, with the ability to attach a debugger, add breakpoints, log, etc. 
 If you're interested in building application using the Vault Application Framework then you will probably want to install the Visual Studio Project Templates: M-Files Online Visual Studio Extension - Visual Studio Marketplace . 
 Regards, 
 Craig.

SearchForPropertyEx doesn't actually return a NULL?

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