# AbstractVisionComponent - How to getTagManager

**URL:** <https://forum.inductiveautomation.com/t/abstractvisioncomponent-how-to-gettagmanager/7467>\
**Category:** Module Development\
**Created:** [October 25, 2013, 8:48am UTC](https://forum.inductiveautomation.com/t/abstractvisioncomponent-how-to-gettagmanager/7467 "2013-10-25T08:48:45Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mazeyrat](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mazeyrat/32/10955_2.png) [@mazeyrat](https://forum.inductiveautomation.com/u/mazeyrat)\
**Post date:** [October 25, 2013, 8:48am UTC](https://forum.inductiveautomation.com/t/abstractvisioncomponent-how-to-gettagmanager/7467/1 "2013-10-25T08:48:45Z")

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I try to read tag in an AbstractVisionComponent  
Ignition 7.6.4rc2

getAppContext() return null, and i can’t use getAppContext().getTagManager() to have an entry point to the Tagmanager for reading tag.

Is it a bug ?  
How to read/write/subscribe Tag into an AbstractVisionComponent ?

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**Author:** ![MoreThanCarbon](https://avatars.discourse-cdn.com/v4/letter/m/6bbea6/32.png) [@MoreThanCarbon](https://forum.inductiveautomation.com/u/MoreThanCarbon)\
**Post date:** [October 25, 2013, 2:55pm UTC](https://forum.inductiveautomation.com/t/abstractvisioncomponent-how-to-gettagmanager/7467/2 "2013-10-25T14:55:34Z")

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Just out of curiosity, why would a component need to look at a specific tag? Wouldn’t you just create a property for that component and let the user define what tag to assign to it?

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**Author:** ![mazeyrat](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/mazeyrat/32/10955_2.png) [@mazeyrat](https://forum.inductiveautomation.com/u/mazeyrat)\
**Post date:** [October 28, 2013, 8:13pm UTC](https://forum.inductiveautomation.com/t/abstractvisioncomponent-how-to-gettagmanager/7467/3 "2013-10-28T20:13:16Z")

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For my vision component (a video player) I need to know if the designer is in preview mode or not.  
To achive it, I doesn’t founded any other method than reading the [System]Client/System/SystemFlags.  
I Kwnow i can add a property on my component for binding this tag on it, but it would be user friendly to avoid this property, by reading the value inside the component.

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**Author:** ![nclemeur](https://avatars.discourse-cdn.com/v4/letter/n/b5e925/32.png) [@nclemeur](https://forum.inductiveautomation.com/u/nclemeur)\
**Post date:** [October 31, 2013, 1:56am UTC](https://forum.inductiveautomation.com/t/abstractvisioncomponent-how-to-gettagmanager/7467/4 "2013-10-31T01:56:05Z")

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[Edit: wrong thread, moving to correct thread, see [viewtopic.php?f=74&t=11223](http://www.inductiveautomation.com/forum/viewtopic.php?f=74&t=11223)]