Accessing UI components on a background thread.

[Frank Rizzo]

Hello,

I know that it's a bad thing to update UI components on a background
thread. But is it fairly safe to access them? I want to iterate
through a tree list.

Thanks.

 

[Nicholas Paldino [.NET/C# MVP]]

Frank,

The only methods on a class that derives from Control that are safe to
invoke from any thread are Invoke, BeginInvoke, EndInvoke and CreateGraphics
(if the handle for the control has already been created). Other than that,
anything to access a property/method on the UI has to be called on the UI
thread, through the Invoke method if from another thread (which will marshal
the call to the UI thread).

 

[Jeffrey Tan[MSFT]]

Hi Frank,

Nicholas has provided the best practice rule for you. Actually .Net Winform
controls encapsulate the Win32 native controls. Since the Win32 native
controls are designed as STA COM threading model, we are not allowed to
call it from second thread.

Regarding your task, you may write a helper method which wraps the code to
iterate through your GUI tree list. Then in the second thread, you may use
Control.Invoke or Control.BeginInvoke methods to call this helper method.
This will ensure the thread safety.

Hope this helps.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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[Jeffrey Tan[MSFT]]

Hi Frank,

Have you reviewed the replies to you? Do they make sense to you? If you
still need any help, please feel free to feedback, thanks.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
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handled working with a dedicated Microsoft Support Engineer by contacting
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[Frank Rizzo]

Hi Frank,

Have you reviewed the replies to you? Do they make sense to you? If you
still need any help, please feel free to feedback, thanks.

Yes, thank you.