Thank you for writing.
The filtering operation needs to be performed on the thread on which the grid was created. It is possible, however, to use a waiting bar from another thread to display that a long running operation is under way.
We have a KB
resource demonstrating how this can be achieved: http://www.telerik.com/support/kb/winforms/details/indicating-progress-in-applications-that-have-their-primary-ui-thread-busy
. I have extended the example to handle the filtering operation. Besides the project, I am also sending you a short video showing the result on my end.
I hope this helps. Should you have further questions please do not hesitate to write back.
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Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms. For more information check out this blog post
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