VB.NET Multi-Threading INVOKE with multiple UI Objects


Recently I was working on a project and everything was fine while debugging but after I create setup and installed the project I Got "System.Runtime.InteropServices.ExternalException (0x80004005): GDI+..." error. I figured out that the error probably caused by codes that like:

My.Resources.MyImage.Save(Application.Startuppath + "/Example.png")


Sub Example()
if My.Settings.PortBusy = False Then
dim t1 as new threading.thread(addressof IsPortOpen)
My.Settings.PortBusy = True
End If
End Sub


 Function operaport() As Boolean
                Dim Client As TcpClient = Nothing
                    Client = New TcpClient("", 9223)
                    Return True
                Catch ex As SocketException
                    Return False
                    If Not Client Is Nothing Then
                    End If
                End Try
    End Function

Sub IsPortOpen()
        Dim brvpt As Boolean = brvport()
        Dim gecpt As Boolean = geckoport()
        Dim cpt As Boolean = chromeport()
        Dim opt As Boolean = operaport()
        If brvpt = True Or gecpt = True Or cpt = True Or opt = True Then
            PortStatus.Checked = True
            PortStatus.Checked = False
        End If
        My.Settings.PortBusy = False
    End Sub

Instead these I Used

Dim copy As Image = My.Resources.MyImage
copy.Save(Application.Startuppath + "/Example.png")


PortStatus.InvokeSafe(New shit(AddressOf IsPortOpen))

But there is another "Threading.Thread" task and it interacts with multiple UI Objects. So how can I "InvokeSafe" multiple Objects in order to use multi-threading tasks that interacts with more than one Object?

Thank You so much For Reading :) .

asked on Stack Overflow Jul 9, 2020 by Sean Flake

1 Answer


This question is a mess but, if I'm getting the gist correctly, you just need to pass a delegate to InvokeSafe for a method that interacts with your multiple UI objects. I'm guessing that InvokeSafe is an extension method that tests the InvokeRequired property and calls the Invoke method of the control you call it on. I have to guess because you haven't bothered to explain. In that case, it doesn't matter what control you call it on. The point of those members is to ensure that you execute code on the thread that owns the specific control. That is going to be the same thread for every form and control, so it matters not which you control you use to get to that thread.

answered on Stack Overflow Jul 10, 2020 by jmcilhinney

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