BusyIndicators's BusyContent appears too late

[Peter]

I'm experiencing a strange behavior: The RadBusyIndicators's content (the yellow circle and the text "Loading...") appears far too late, but the BusyIndicator becomes grey at the right moment. The content (progress bar) appears not until the time-consuming action is over.

Here is what I'm doing in Pseudocode:

MyDialog dialog = new Dialog();             // A Window that contains the BusyIndicator
dialog.myRadBusyIndicator.IsBusy = true;    // Startup with the BusyIndicator activated
dialog.Dispatcher.BeginInvoke(new System.Action(MyLoginAction));   // Start some time-consuming action in the Background
dialog.ShowDialog();                        // Show the user a Dialog with busy information

Problem: The yellow circle in the BusyIndicator shows up AFTER the time-consuming action is over, but Busy-State (graying) is activated correctly when the Dialog pops up.

Some intricate threading problem?

[Ivo]

Hi Peter,

The code executed into a Dispatcher.BeginInvoke always run on the UI thread. You will have to execute the time-consuming code into a BackgroundWorker to avoid this. You can find a sample example attached.

Kind regards, Ivo
the Telerik team

[Peter]

Thanks a lot, Ivo!

That was the solution to my problem. Great support! 

The lesson learned (for me and others) is:

When using the RadBusyIndicator, you should always run the time-consuming code in a BackgroundWorker or in a separate thread - even if UI Dispatcher.BeginInvoke seems to work at first sight...