Like indicated in the topic,
There is a business requirement allow user to drag a tag from tag brower tree, and the history value of this tag will display in the chart.
I know easy chart can provide such functionality, but need enable the "history" property for this tag, in my case, the data is not required saved to DB. Only for user to view when he opens the monitor window.
Is there a simple way to realize such function without too much script in vision & perspective ?
No, tags to not have any way to remember their trend except via history.
With a dataset and a timer you could shift data into the dataset every x seconds and display that.
But that will only be data that is available while the view/window is open and being viewed.
We did this a long time ago for quick dirty trends where we didn't want to have to historize every tag.
I included a function called recorder() in my Simulation Aids module that does this in one package. It is not suitable for production environments.
Are you using easy chart to display the data ? Does it allow user to select multiple tags and display in one chart ?
Easy Chart can only display trends from a database or a historian (which is typically indirectly from a database). The Vision Classic Chart can display from any arbitrary dataset. Similar constraints apply to Perspective's Power Chart versus Time Series and XY Charts.