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Recently I developing a IM software, and want to dynamics add a tab page on the form when a new private chat request is arrived, but I have a problem about .NET is not allowed me to add a control when the code is running cross threads.

I have try using delegate to invoke this cross thread action, but it still not works....

Now I have no idea about this problem.

Here is the code how i dynamics add a control.

''' <summary>
''' 函数返回Key,添加的新的标签页控件的哈希值,不能够跨线程添加控件
''' Dynamics add a tabpage control on the form 
''' </summary>
''' <returns></returns>
''' <remarks></remarks>
Public Function Add(Control As Control) As Integer
    Dim Panel As PagePanel = New PagePanel

    ControlToAdd = Panel

    SyncLock ControlToAdd

        Call _InternalForm.Invoke(New MethodInvoker(AddressOf AddControlInvoke))

        ControlAddToPanel = Control

        SyncLock ControlAddToPanel

            Call ControlToAdd.Invoke(New MethodInvoker(AddressOf PanelAddControlInvoke)) ' !!! The code stuck running at here.

        End SyncLock

    End SyncLock

    Call Panel.Controls.Add(Control)
    Control.Dock = DockStyle.Fill

    Dim Key As Integer = Panel.GetHashCode()
    Call Add(Key, Panel)
    Call [Select](Panel)

    Return Key
End Function

Dim ControlToAdd As PagePanel
Dim ControlAddToPanel As Control

Private Sub PanelAddControlInvoke()
    Call ControlToAdd.Controls.Add(ControlAddToPanel)
End Sub

Private Sub AddControlInvoke()
    Call _InternalForm.Controls.Add(ControlToAdd)
End Sub

1 solution

If you are using WinForms then:

If you are using xaml then:
Share this answer
Mr. xieguigang 谢桂纲 6-May-15 11:32am    
Control.BeginInvoke(MethodInvoker) is still not working... the code is still stuck running at here
InbarBarkai 6-May-15 23:48pm    
You're locking the panel before using it on another place.
That's why you get a deadlock.
The SyncLock command prevents any other thread from using the object. Since you start a new thread to add the control, it tries to access the panel but stops because of the lock.

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