Need Help Understanding a dropdown

Ignition
1

I am just trying to display the selected item of a dropdown, the dropdown is being populated by a sql query. Right now there are two item in the dropdown, test1 and test 2.

I have the property change of the dropdown populated with “print event.source.selectedItem”

When i click between test1 and test2 the selectedItem gets printed three times on the screen and im not sure why?

My goal is to run a query of the selected item after it has been selected but i need to understand how it functions first, thanks!

2

The propertyChange event is triggered for every property that changes on a component. When you select a value, you are changing the selectedIndex, selectedValue, and selectedLabel at a minimum. You should use the event.propertyName property to limit when your changes are made:

if event.propertyName == "selectedIndex":
	#do something

That helps, I’m sure, but there’s an easier way to do what you want, I think. If you want to update a table query based on the selection, you only have to include a reference to the dropdown value in your query for the table:

table.data:

SELECT columns 
FROM tablename
WHERE fieldname = '{Root Container.Dropdown.selectedStringValue}'

Ignition will immediately refresh the table query when the value changes.

3

Thanks for the quick response, i actually want to run a separate query on a different table based on the value selected from the dropdown.

so i take it that since three items change that is why when i select an item it shows up three times? Thanks again

4

You should play with the code. See what happens when you do:

print event.propertyName
5

i guess since i wasn’t filtering anything out i was seeing all changes, ill play around a little more later. Thanks for your help! I appreciate it

6

where can i get a list of all of the property change events associated with them? thanks

7

[quote=“drewdin”]
so i take it that since three items change that is why when i select an item it shows up three times? Thanks again[/quote]
Yes, that is correct.

I don’t think there is any list availabe for “property change events”. You need to run “print event.propertyName” and modify the values of properties and see which ones get printed.

8

This from the Ignition Manual is helpful:

inductiveautomation.com/support/ ... _types.htm

Best,
Nick Mudge