Multi-threading Debugging Enhancements in Visual Studio 2008

Hello,

I've included the code for a class that I'm struggling with.
(I've omitted the FormStatus object, but any form with a lblStatus label would do).

The purpose of the class is to display a StatusForm on a separate thread.

The StatusForm has a rotating logo, and a label that can get updated to reflect status on the main thread...

Sample usage from some class, or form...(within a loop or long running routine)

'Would be called to display a "TopMost" form indicating status..
ClsAsyncStatusDisplay.DisplayStatus("Doing something...")
ClsAsyncStatusDisplay.DisplayStatus("25% Complete...")
ClsAsyncStatusDisplay.DisplayStatus("50% Complete...")

'Would be called to hide the form from view
ClsAsyncStatusDisplay.HideStatus()

My class works 99% of the time, but occassionally the class "locks up"...

I'm open to ANY suggestions! -- I'm sure there's a much better tecnique than this...

Thanks.






Option Strict On
Option Explicit On

Public Class ClsAsyncStatusDisplay

Private Shared _thisInstance As ClsAsyncStatusDisplay

Private Message As String = ""
Private WithEvents StatusThread As System.Threading.Thread
Private WithEvents StatusForm As FormStatus
Private Delegate Sub SetTextCallback(ByVal [text] As String)

Private _DelegateSetTextCallBack As New SetTextCallback(AddressOf SetText)

Private Delegate Sub CloseFormCallBack()

Private _DelegateCloseFormCallBack As New CloseFormCallBack(AddressOf CloseForm)

Private Sub New()

'Forces Singleton Class

End Sub

Public Shared Sub DisplayStatus(ByVal msg As String, Optional ByRef obj As Control = Nothing)

If IsNothing(_thisInstance) Then

_thisInstance = New ClsAsyncStatusDisplay

End If

If IsNothing(_thisInstance.StatusThread) Then

_thisInstance.StatusThread = New System.Threading.Thread(AddressOf _thisInstance.ShowForm)

System.Threading.Thread.Sleep(750) 'Don't display status unless outside process is taking almost 1 second to complete....

_thisInstance.StatusThread.Start()

ElseIf Not IsNothing(_thisInstance.StatusThread) And _thisInstance.StatusThread.ThreadState = Threading.ThreadState.Stopped Then

_thisInstance.StatusThread = Nothing

_thisInstance.StatusThread = New System.Threading.Thread(AddressOf _thisInstance.ShowForm)

System.Threading.Thread.Sleep(750) 'Don't display status unless outside process is taking almost 1 second to complete....

_thisInstance.StatusThread.Start()

Else

_thisInstance.SetText(msg)

End If

_thisInstance.Message = msg

End Sub

Public Shared Sub HideStatus()

If Not IsNothing(_thisInstance.StatusForm) Then

_thisInstance.CloseForm()

End If

End Sub

Private Sub ShowForm()

Try

If IsNothing(_thisInstance.StatusForm) OrElse _thisInstance.StatusForm.IsDisposed Then

_thisInstance.StatusForm = New FormStatus

End If

SetText(_thisInstance.Message)

If _thisInstance.StatusForm.IsDisposed = False Then

_thisInstance.StatusForm.ShowDialog()

End If

Catch ex As Exception

'Do Nothin'

Me.CloseForm()

End Try

End Sub

Private Sub CloseForm()

Try

If _thisInstance.StatusForm.InvokeRequired Then

_thisInstance.StatusForm.Invoke(_DelegateCloseFormCallBack)

Else

If Not IsNothing(_thisInstance.StatusForm) And Not _thisInstance.StatusForm.IsDisposed Then

_thisInstance.StatusForm.Close()

End If

End If

Catch ex As Exception

'Do Nothin'

End Try

End Sub

Private Sub SetText(ByVal [text] As String)

Try

If Not IsNothing(_thisInstance.StatusForm) AndAlso _thisInstance.StatusForm.Disposing = False AndAlso _thisInstance.StatusForm.IsDisposed = False Then

' InvokeRequired required compares the thread ID of the

' calling thread to the thread ID of the creating thread.

' If these threads are different, it returns true.

If _thisInstance.StatusForm.lblStatus.InvokeRequired Then

_thisInstance.StatusForm.lblStatus.Invoke(_DelegateSetTextCallBack, New Object() {[text]})

Else

_thisInstance.StatusForm.lblStatus.Text = [text]

End If

End If

Catch ex As Exception

'do nothin

Me.CloseForm()

End Try

End Sub

End Class