# Check String Parameter to Enable/Disable Tag

**URL:** <https://forum.inductiveautomation.com/t/check-string-parameter-to-enable-disable-tag/69657>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [February 9, 2023, 8:44pm UTC](https://forum.inductiveautomation.com/t/check-string-parameter-to-enable-disable-tag/69657 "2023-02-09T20:44:57Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [February 9, 2023, 8:44pm UTC](https://forum.inductiveautomation.com/t/check-string-parameter-to-enable-disable-tag/69657/1 "2023-02-09T20:44:57Z")

</div>

I have a string parameter that is used in the OPC path of a tag. I want to disable the tag if the parameter is not provided (empty). My binding on the enabled property of the tag looks like so:

```auto
!( isNull({Read_Tag}) || {Read_Tag} = "" )

```

I'm not sure if an empty string returns "", or Null, so I used both.

I get a configuration error on the tag:

> Error\_Configuration("Bad\_AttributeIdInvalid: The attribute is not supported for the specified Node.")

Is there something wrong with the binding?

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<div class="post-metadata">

**Author:** ![mmunin](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mmunin](https://forum.inductiveautomation.com/u/mmunin)\
**Post date:** [February 9, 2023, 8:55pm UTC](https://forum.inductiveautomation.com/t/check-string-parameter-to-enable-disable-tag/69657/2 "2023-02-09T20:55:25Z")

</div>

You can't use expression language in the binding of the `enabled` property, unfortunately. Fortunately, you CAN just use `{Read_Tag}` and it will cast any non-empty string values of your property to "True"

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<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [February 9, 2023, 9:00pm UTC](https://forum.inductiveautomation.com/t/check-string-parameter-to-enable-disable-tag/69657/3 "2023-02-09T21:00:43Z")

</div>

If that's the case, it really should stop highlighting expression statements as if the expression syntax applies. For instance:

![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/5/3/53e796b5331d9b4ace396dbae2df79d3cd38c907.png)  
"if" should not be highlighted as a function if this is not the expression language.