How to exchange date between GUI and a background thread?

[Jerald.Zhang]

I will start a global background task in a thread after client start, but how could I visit UI components in this thread?

[Jerald.Zhang]

I now use:

1. Client tags
2. Window or control’s custom properties

Is this a right way?

[bkarabinchak.psi]

This background task thread - are you running it on the gateway or via a background thread in the client? If via a background thread on the client using system.util.invokeAsynchronous then you necessarily must use system.util.invokeLater to affect the GUI, otherwise you risk freezing your GUI. The documentation has an example - system.util.invokeAsynchronous - Ignition User Manual 7.8 - Ignition Documentation

[pturmel]

@Jerald.Zhang

Is this a right way?

Client tags are a safe way to pass data between GUI (foreground) and an asynchronous thread (background). Directly accessing window objects and the components within them is not safe. You have to delegate to short functions in the foreground to make any changes and safely read values. This topic discusses the relevant techniques:

Update GUI via Asynchronous thread

I’ve got a script I am experimenting with that can take a lot of time to execute, so I now use the system.util.invokeAsynchronous to run the script in a separate thread to keep the GUI from locking up. I am using the asynchronous thread to copy files from one place to another, and I would like to show the progress of the file copy with a progress bar. How would I go about this? I am importing a few python libraries to do this. import shutil def fileTransfer(): path = system.file.openFile() …

[Jerald.Zhang]

Actually, Your answer makes me realized that my question is how to exchange data between thread and GUI. I will use client tags, Thanks for you suggest.