Thread safe calls to windows forms controls

Question

I have a text box that constantly updates value coming in from a serial device. When I compile the code and build the project in .exe format everything works fine. But when I run the project from the VS 2008 environment then it displays a message box saying that the control 'textbox' accessed from a thread other than the thread it was created.

Can anyone make suggestions to the problem. It points to the following line in the code:
Me.tReading.Text = Format(reading, "#0.00000")

Vulpes · Answer

To avoid this error you'll need to marshal any changes to controls back to the UI thread which created them. To do this first add this Sub to your Form containing the line to be executed: Sub tReading_Update() Me.tReading.Text = Format(reading #0.00000) End Sub Now where the error occurred replace the offending line with these lines: Dim mi As MethodInvoker = AddressOf tReading_Update Me.Invoke(mi) If it doesn't work or only works intermittently then replace the last line with the asynchronous version: Me.BeginInvoke(mi)

latika singh · Answer

Thank you!