How to read a Length-Stretch parameter into an attribute or tag

[Anonymous]

I am attempting to modify the attached block. It contains several visibility states.

The end goal is to have the attribute, "SL_DH_SIZE" read the distance of "SLIDER-DH WIDTH/HEIGHT", so that when the block is inserted and either the slider or double hung window visibility state is selected and I then stretch the length of the window to fit the opening, the attribute updates (after regen) and I can see what size that window is on the drawing.

I have tried everything I can think of or find on the web. All I am getting is "#######"

Suggestions or solution are much appreciated. The file is uploaded for anyone who wants to play around.

[Libbya · Accepted solution]

Your issue is that the attribute property constant=YES.  If an attribute has a constant value it cannot ever update and the field fails.

[TiStars]

Can't it be updated automatically without Regen?

Thanks

[Anonymous]

Awesome. Thank you. Another tutorial called for Constant to be set. Shrug.

Thank you very much!!!

[Libbya]

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@TiStars wrote:

Can't it be updated automatically without Regen?

Thanks

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No.  Fields do not ever automatically and immediately update.  You can set the fieldeval system variable to its highest setting (31) and it will update on open, save, plot, etransmit, and regen but not immediately without one of those triggers.  

[TiStars]

Thank you very much !