PropertyChange Script Error

I have a Dropdown object on one of my windows, this object is populated by a Named Query.

This Dropdown is how a PDF is selected for the PDF Viewer.

While in test mode everything works just fine, when I actually run with a Client everything works just fine except when I leave(close) this window and move to another.

I get a scripting error - it tells me that a null value can’t be used to open the pdf.

So I’m assuming the the property change event fires for the dropdown when the window closes and this is why I get the NULL error (Nothing has been selected) But how do I handle this error so my program will work correctly.

Here is my script for the Dropdown object

# Check to see if the property that changed was the Selected Value property.
if event.propertyName == "selectedValue":
 	# Run the query to grab the file name and bytes using the new selected ID value. = system.db.runNamedQuery("Sample2", {"fileid":event.source.selectedValue})

    # Grab the file bytes and name from the same row.

bytes =, "data")

name =, "filename") 
    # Load the bytes into the PDF Viewer component.
event.source.parent.parent.getComponent('Container').getComponent('PDF Viewer').loadPDFBytes(bytes, name)

Try adding a check for the value like this:

if propertyName == "selectedValue":
     fileid = event.newValue
     if fileid > -1:
 = system.db.runNamedQuery("Sample2", {"fileid":fileid})


Check your indentation. It looks like your later lines of code run for any property, not just for selectedValue.