Timer Problem

[CoMMiE]

Hi,
I tried to do a ad rotator stuff on a form,but the problem is everytime i tried to load a picture to a dynamically created picturebox during the time_elapsed event, it gave me this error.

"Run-time exception thrown : System.ArgumentException - Controls created on one thread cannot be parented to a control on a different thread."

anyone knows anysolution to this problem


Thanks

[powdir]

the timer must run on a different thread than that of the form - use delegates and the forms 'invoke' method to marshall the values between threads. I could post you an example later (out for the next few hours) if that is any good?

[CoMMiE]

Thanks Powdir!
It will be nice if you can provide some samples

[powdir]

Ok, here a quick example. Sorry i had to use a worker thread as a substitute for a timer callback - i have also never used the AdRotator but i guess the principle will be the same i.e. using the forms invoke method. Hope this points you on the right track

Create a simple form with a command button and a treeview.

Public Delegate Sub UpdateTreeView(ByVal str As String)
    '
    'set up a worker thread
    'change the addressof this thread to point to AddNodesFail 
    'and see it fail. Then change it back to ThreadingAddNodes
    Public tr As New Threading.Thread(AddressOf ThreadingAddNodes)

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        tr.Start()
    End Sub
    '
    Private Sub ThreadingAddNodes()
        Dim UpdateTreeViewDeleg As New UpdateTreeView(AddressOf AddNodes)
        'set up the arguments array that will be marshalled across the to the UI thread
        'from the worker thread
        Dim args() As String = {"Hello from thread "}
        'and send it across to the UI using the forms invoke method
        Me.Invoke(UpdateTreeViewDeleg, args)
    End Sub
    '
    Private Sub AddNodes(ByVal str As String)
        'this sub is used to demo passing arguments across threads
        Dim i As Integer
        For i = 0 To 100
            TreeView1.Nodes.Add(str & CStr(i))
        Next
    End Sub
    '
    Private Sub AddNodesFail()
        'use this sub to test for failure
        Dim i As Integer
        For i = 0 To 100
            TreeView1.Nodes.Add("Hello from failure" & CStr(i))
        Next
    End Sub

...that any help?

Cheers

[powdir]

PS...looking at your original question (helps if i read it fully ) it would seem that the dynamically created control will have to be passed as the argument in the invoke method...