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I haven't worked much with threads - can you update a global collection shared across threads?<br />
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If so you could populate the dropdown &quot;just in time&quot; when the user opens the list.
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&gt;&gt;can you update a global collection shared across threads<br />
Yes, you can, but you have to be aware to avoid concurrent access, you can use Monitor class like:<br />
<br />
Monitor.Enter(theCollectio<wbr />nObj)<br />
' do something with the collection object here<br />
Monitor.Exit(theCollection<wbr />Obj)<br />

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Maybe I misunderstood something. The main class is called 'config' and the worker thread class is called 'LetsPrint'. I tried this code in the LetsPrint class and called it with WriteThreadLog(&quot;Test&quot;), but nothing was added to the listbox on the 'config' form. Can someone please point out what I'm doing wrong?<br />

<pre><code class="code-1 nolinks" id="code-124421"><span>    Private Delegate Sub MessageDelegate(ByVal _message As String)</span>
<span>    Private Sub WriteThreadLog(ByVal Message As String)</span>
<span>        Dim args As Object() = {Message}</span>
<span>        If config.InvokeRequired Then</span>
<span>            config.Invoke(New MessageDelegate(AddressOf WriteThreadLog), args(0)) </span>
<span>        Else</span>
<span>            config.monitorLog.Items.Add(args(0))</span>
<span>        End If</span>
<span>    End Sub</span>
</code></pre>
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OK, I figured it out myself: I created an event on the worker thread called LogUpdated and just handled the event from the main form. It's working great. Thanks for all your suggestions.
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I'll give you the points, since you got me looking in the right direction. Thanks again.
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I have a VB.NET (2005) multithreaded program. The main thread has a listbox on it that I am using as sort of a log. Each time an event happens, it adds an item to the listbox. I need the 2nd thread to be able to add items to the listbox as well. I've tried several things without success. Can someone help?
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I have a VB.NET (2005) multithreaded program. The main thread has a listbox on it that I am using as sort of a log. Each time an event happens, it adds an item to the listbox. I need the 2nd thread to be able to add items to the listbox as well. I've tried several things without success. Can someone help?

How to Add Listbox item from a different thread?

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