# "error performing subscript operation" on Perspective view text box bindings **URL:** \ **Category:** Ignition\ **Tags:** ignition81, perspective\ **Created:** [January 16, 2023, 2:35pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629 "2023-01-16T14:35:59Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![jeff.ryan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jeff.ryan/32/25543_2.png) [@jeff.ryan](https://forum.inductiveautomation.com/u/jeff.ryan)\ **Post date:** [January 16, 2023, 2:35pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/1 "2023-01-16T14:35:59Z")
![CaptureNullProb2](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/9/c9e515b5b02f869efb3fa857066922a616ba7d11.jpeg) ![CaptureNullProb](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/b/8b18712266298e61cadd638c03d9d5e9eed7b569.jpeg) In a Perspective View, many text boxes that all have a tag history binding to OPC tags, I'm getting 'null' displayed rather than valid values, and in the warning for the property, per the attached message it is Error\_ExpressionEval("Error performing subscript operation"). I have a good connection to the PLC tags that these bindings are to, and the binding previews show ok, per the attached screen shot as well. Also, I can add a new text box and create the same kind of binding to the same tag(s) and it displays / works OK. So... , what might be going on here with this problem/error on the existing components, am I missing something obvious? Thanks much! ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [January 16, 2023, 2:48pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/2 "2023-01-16T14:48:53Z")
I suspect there's more to that binding than you're showing us. Make that binding window taller and screenshot it again. ---
**Author:** ![jeff.ryan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jeff.ryan/32/25543_2.png) [@jeff.ryan](https://forum.inductiveautomation.com/u/jeff.ryan)\ **Post date:** [January 16, 2023, 2:51pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/3 "2023-01-16T14:51:50Z")
![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/e/ae4ec88efb2ce35ec04ed4ec426c4f9a2e6a8b49.png) There you go, about as tall as I can get, thx. ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [January 16, 2023, 3:23pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/4 "2023-01-16T15:23:45Z")
Can you make a table and use that same binding on it, except without the expression ? ---
**Author:** ![jeff.ryan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jeff.ryan/32/25543_2.png) [@jeff.ryan](https://forum.inductiveautomation.com/u/jeff.ryan)\ **Post date:** [January 16, 2023, 3:31pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/5 "2023-01-16T15:31:10Z")
![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/9/697f3ac8662c345240c28f1d175505464b056cac.png) Yeah, here it is. I made sure that all details were the same, with historical vs realtime and the same date range. Let me know if that's wasn't what you were looking for. Thanks. ---
**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\ **Post date:** [January 16, 2023, 3:41pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/6 "2023-01-16T15:41:13Z")
I'm... not sure where to look. The `Error_ExpressionEval("Error performing subscript operation` error suggests that there's an issue when trying to retrieve data from the dataset with the subscript operator (`[0,2]`), but... I don't know what that issue would be. One last shot: Try changing the return format of the query from dataset to document, and in the expression change `{value[0,2]}` to `{value}[0]['durationOff']`, see if that also throws an error. ---
**Author:** ![jeff.ryan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jeff.ryan/32/25543_2.png) [@jeff.ryan](https://forum.inductiveautomation.com/u/jeff.ryan)\ **Post date:** [January 16, 2023, 3:54pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/7 "2023-01-16T15:54:57Z")
1. When I do your suggestion, changing it to 'Document', changing the format Transform, then I get null value returned, but not null outlined in red as if there is an error. 2. Interesting find since my last reply when I was trying this! If I remove the tag path, then apply, OK to exit and save the project, and then go back into the binding, re-add the tag by browsing to it again and then apply, OK, exiting and save the project, it fixes it! The correct value then populates without error. I have a LOT of text boxes on the view to do this to, but it would fix it. So.., some kind of bug/corruption perhaps? Thanks again Pascal for the help. ---
**Author:** ![Steve\_Laubach](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/steve_laubach/32/60900_2.png) [@Steve\_Laubach](https://forum.inductiveautomation.com/u/Steve_Laubach)\ **Post date:** [January 16, 2023, 4:53pm UTC](https://forum.inductiveautomation.com/t/error-performing-subscript-operation-on-perspective-view-text-box-bindings/68629/8 "2023-01-16T16:53:01Z")
You might have had a similar situation if you did a refreshBinding on the bindings.