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POUpdate UI form from worker thread
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copied!<p>I am new to multi-threading in VB.NET and have come across a problem whereby I am wanting to append text to a text box on a form from a service thread running in the background.</p> <p>The application I am developing is a client/server listener, I have been able to get the client and server PC's to talk with each other (confirmed through MsgBox), however I am now struggling to get the service thread on the server to append the text to the textbox, nothing vissible occurs.</p> <p>I have a form named testDebug which calls a class (RemoteSupport), this class does all the handshake tasks and updates the textbox with the connection data.</p> <p>Can anyone identify where I am going wrong and point me in the right direction?</p> <p>The following is the code I have: The form has a textbox named txtOutput, the following is from the remoteSupport class</p> <pre><code>Dim outMessage As String = (encoder.GetString(message, 0, bytesRead)) MsgBox(outMessage, MsgBoxStyle.Information, "MEssage Received") If outMessage IsNot Nothing Then If testDebug.InvokeRequired Then ' have the UI thread call this method for us testDebug.Invoke(New UpdateUIDelegate(AddressOf HandleClientComm), New Object() {outMessage}) ' Else testDebug.txtOutput.AppendText(outMessage) End If 'RaiseEvent MessageReceived(outMessage) // a previous attempt to use custom events End If </code></pre> <p>I am not sure if the invoke method is the ideal solution or if custom events are, I have spent some time on trying to get custom events to work, but these didnt work either.</p> <pre><code> // In the RemoteSupport class Public Delegate Sub MessageReceivedHandler(ByVal message As String) Public Shared Event MessageReceived As MessageReceivedHandler // Located throughout the RemoteSupport class where debug information is required. RaiseEvent MessageReceived(outMessage) // Located in the code-behind of the form Private Sub Message_Received(ByVal message As String) testDebugOutput(message) // this is a function I have created // to append the text to the text box End Sub </code></pre> <p>The code supplied has been cut down so if there is anything else that you want to see or any questions please let me know.</p> <p>Thanks for your assistance.</p> <p>EDIT: I have uploaded the two VB files (form and class) to my site, I would appreciate it if someone could have a look at it to help me with identifying the problem with the UI not updating.</p> <p>I have tried a few other things but nothing seems to be updating the UI once the worker thread has started.</p> <p>Form: mulholland.it/testDebug.vb.txt Class: mulholland.it/remoteSupport.vb.txt</p> <p>Thanks for your assistance.</p> <p>Matt</p>

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