Problem with Invoking (Delegate)

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Cross-thread operation not valid: Control 'lsvClients' accessed from a thread other than the thread it was created on.

How to solve the error above? I think I must create other method and invoke it. But unfortunately, I don't know how. Here is the code that generates such error

VB

Private Delegate Sub _AddClient(ByVal client As Socket)
   Private Sub AddClient(ByVal client As Socket)

       If InvokeRequired Then
           Invoke(New _AddClient(AddressOf AddClient), client)
       End If

       Dim lvi As New ListViewItem(client.LocalEndPoint.ToString())
       lvi.Tag = client
       lsvClients.Items.Add(lvi)
   End Sub

lsvClients is ListView. All I want is when a client connected to the server (code above) it will be listed on the listview. Thanks in advance.

Posted 9-Dec-11 8:26am

adadero

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Addy Tas · Accepted Answer · 2011-12-09T11:37:00

Solution 1

Hi Adadero, long time no see ;)

As you seem to be mixing VB and C# (good for you by the way) I'll just post a related issue from your other issue In C#. No doubt you can modify this yourself to the VB equivalent.

C#

if (InvokeRequired)
{
	Invoke(new MethodInvoker(delegate()
	{
		if (txtChat != null)
		      txtChat.Text += text;
     	} ));
}

Now it seems clear that you need to replace the txtChat with the ListView.

As you know; if you have onother question; just ask.

Cheers, AT

Posted 9-Dec-11 11:37am

Addy Tas

Comments

adadero 10-Dec-11 1:19am

Hi. It's work perfectly. Again, I have to thank you. Your solutions are very helpful. You come exactly when I need help. Anyway, I am coding with both language (VB and C#) and actually I prefer C# since it's simpler but VB is easier anyhow. I hope you can help me when I have problem :). Here is the code as you suggest, and it works.

Private Delegate Sub _AddClient(ByVal client As Socket)
Private Sub AddClient(ByVal client As Socket)

If InvokeRequired Then
Invoke(New _AddClient(AddressOf AddClient), client)
Invoke(New _AddLV(AddressOf AddLV), client)
End If
End Sub

Private Delegate Sub _AddLV(ByVal client As Socket)
Private Sub AddLV(ByVal client As Socket)
Dim lvi As New ListViewItem(client.LocalEndPoint.ToString())
lvi.Tag = client
lsvClients.Items.Add(lvi)
End Sub