Windows Form Threading Problem in VB.NET

Question

Hi everybody, I have been developing a VB.NET application using DirectX to display various multimedia within a screen (windows.form). The application displays consecutive screens based on user-defined schedule. In order to fully load the next screen in the background, so that it makes transition between screens going smoothly, I am using Threading technique. However, the screen never appears, in contrast it works fine when I do not use the Threading, but the next screen never loaded properly (some directX components cannot be loaded) and transition does not go smoothly. Here it is my source code: Dim ShowFormThread As Thread Friend WithEvents tm As New System.Windows.Forms.Timer 'frmCanvas is a class inherits from System.Windows.Forms.Form Friend WithEvents RunForm, OldForm As frmCanvas Private Sub TickMe() 'timer to trigger this module tm.Enabled = False 'assign the current/running screen (RunForm) into OldForm OldForm = RunForm 'call module that assign RunForm into the next screen 'also assign next interval timer LoopFunc() 'keep the running screen (OldForm) runs at front If Not OldForm Is Nothing Then OldForm.BringToFront() End If If RunForm Is Nothing Then tm.Enabled = False tm.Stop() Me.Close() Process.GetCurrentProcess.Kill() Exit Sub End If 'this commented part to show the next screen if i do not use Thread method '''RunForm.WindowState = FormWindowState.Minimized '''RunForm.Opacity = 1 '''RunForm.Visible = False '''RunForm.SendToBack() '''RunForm.Show() '''RunForm.SendToBack() '''RunForm.Visible = True '''RunForm.WindowState = FormWindowState.Maximized '''RunForm.Location = New System.Drawing.Point(0, 0) 'if start the first screen, i do not use Thread method If blnStartPlay Then Call ShowForm() blnStartPlay = False Else 'second screen onwards, i use Thread method If Not ShowFormThread Is Nothing Then If ShowFormThread.IsAlive Then ShowFormThread.Abort() ShowFormThread = Nothing End If End If ShowFormThread = New Thread(AddressOf ShowForm) ShowFormThread.Start() 'make sure the thread of next screen stop, it means letting the next screen 'fully loaded at background If ShowFormThread.IsAlive Then While ShowFormThread.IsAlive End While End If End If If Not OldForm Is Nothing Then 'make the current/running form (OldForm) moving to right as horizontal transition Call HorizontalTransition(OldForm.Width) RunForm.BringToFront() Dim z As Double For z = OldForm.Controls.Count - 1 To 0 Step -1 OldForm.Controls(z).Dispose() Next OldForm.MainFrm = Nothing OldForm.Dispose() OldForm = Nothing End If GC.Collect() If Not Running Then tm.Stop() tm.Enabled = False End If Thread.Sleep(1000) tm.Enabled = True End Sub Private Sub tm_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles tm.Tick TickMe() End Sub Private Sub HorizontalTransition(ByVal intWidth As Integer) Dim intTransition As Integer For intTransition = 0 To intWidth Step 100 OldForm.Location = New System.Drawing.Point(intTransition, 0) Next Exit Sub End Sub Private Sub ShowForm() RunForm.WindowState = FormWindowState.Minimized RunForm.Opacity = 1 RunForm.SendToBack() RunForm.Show() RunForm.SendToBack() RunForm.WindowState = FormWindowState.Maximized RunForm.Location = New System.Drawing.Point(0, 0) Exit Sub End Sub The RunForm at the second screen onwards never appear after I call it using Thread method via method ShowForm. Please help me on this problem. Thanks a lot in advance. cheers, nugie73